Bounty Question: Using the ethereum.core.fact_blocks table, 

• Do certain miners prefer mining blocks with lower transaction count? 
• Do certain miners only mine blocks with high transaction count? 
• You can define what can be considered low or high transaction count based on the transaction count distribution

📌 What is Ethereum mining?

Mining is the process of creating a block of transactions to be added to the Ethereum blockchain. The word mining originates in the context of the gold analogy for crypto currencies. Gold or precious metals are scarce, so are digital tokens, and the only way to increase the total volume is through mining. This is appropriate to the extent that in Ethereum too, the only mode of issuance post launch is via mining. Unlike these examples however, mining is also the way to secure the network by creating, verifying, publishing and propagating blocks in the blockchain.

> Mining ether = Securing the Network

Ethereum, like Bitcoin, currently uses a proof-of-work (PoW) consensus mechanism. Mining is the lifeblood of proof-of-work. Ethereum miners - computers running software - using their time and computation power to process transactions and produce blocks.

💡 Methodology

• At first, in order to get a overview of the number of transactions in each block, the average and median number of transactions per block was obtained. The point is that there are a large number of blocks in which no transaction has occurred. Most of these blocks are the initial blocks of the Ethereum network. In the distribution of the number of transactions of each block, these blocks are also present under the title of "zero transaction", but they are excluded from the other analyzes performed.
• One of the features of symmetrical distribution is that median and average are equal. The closeness of these two numbers in the analysis done by us, tells us that there is an almost symmetrical distribution in the number of block transactions.
• But to define how many transactions in each block should be considered as "Lower Transaction Count" and "Higher Transaction Count", the result of the average number of transactions per block was used. In our definition, if the number of transactions is less than the average number of transactions (number of transactions per block <= 123), as "Lower Transaction Count" and if it is more than the average number of transactions (number of transactions per block > 123), were considered as "Higher Transaction Count".
• Based on the above definition, each block that was in these ranges was given the titles "Lower Transaction Count" and "Higher Transaction Count".
• Finally, it was calculated how many blocks of each miner (with at least 5 blocks) were placed in each of these categories and what percentage of the total number of mined blocks it made up. If 60% or more of the blocks of a miner is in one of the "Lower Transaction Count" or "Higher Transaction Count" categories, She/He is known as a miner who tends to mine her/his blocks with lower or higher transactions respectively. Of course, it is natural that this 60%, which was considered as a range, can change and show different results as a whole.

• Since the beginning, about 1.71b transactions have been done in the Ethereum network. These transactions were made in 13.88m blocks (with at least one transaction) and ==by 4.65k miners==. On average, each block included ==123== transactions.

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• In the donut chart, the distribution of the number of transactions of blocks can be seen that about 27% of all blocks have between 0 and 50 transactions. About 16% of the blocks had between 50 and 100 transactions, slightly more than 15% of the blocks had between 150 and 200 transactions, and 14% of the blocks had between 50 and 100 transactions. This means that the first 4 categories (which represent from 0 to 200 transactions per block) constitute 72% of all blocks. That is, 72% of the blocks have less than 200 transactions.

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• What seems clear is that if our assumption is correct for the division of blocks; Therefore, the "Lower Transaction Count" category has the upper hand in terms of the number of miners and about 32% of all miners are in this category. This means that miners tend to mine more than 60% of their blocks with lower transactions. For the "Higher Transaction Count" category, only slightly more than 5% of miners tended to mine more than 60% of their blocks with a higher transaction count than the average number of transactions per block.

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• On the other hand, if we pay attention to the distribution of "% of Blocks", interesting points can be seen. The most prominent difference between the two categories is that there are many miners in the "==Lower Txs==" category, all of whose blocks fall into this category. If we want to talk by numbers, we can say that 83.3% of miners in the "Lower Txs" category (which is ==26.4% of all miners==) mined all their blocks with lower transactions. The situation with the "Higher Txs" category is generally different. There is only ==8.57%== of miners in that category (which is ==only 0.45% of all miners==) tended to mine all their blocks with more transactions than the average number of transactions per block.

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• In the scatter chart, the difference between the two categories can be well seen, where the concentration of points on the 100% line in the "Lower Txs" category is clearly visible, but in the "Higher Txs" category, the concentration of points cannot be seen in He saw a certain place of the chart prominently.

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• But if we set the range to percentages higher than 60%, how will the result be? To answer this question, it was checked in both categories that if the range is increased from 60% to 100%, 5% to 5%, how would the situation be. In the donut charts above, this analysis can be evaluated.

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• Due to the fact that there are a large number of miners in the "==Lower Txs" category (86.4% of all miners in this category), all of their blocks are included in this category, the distribution results obtained considering that all categories are 100% are included, they do not show many differences and the distribution of different ranges are close to each other. But in case of "Higher Txs" category the situation is different. In this category, as the range has increased, there has been a clear decrease in the number of miners.

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• The Area chart compares these two categories from this point of view. As can be seen in the graph, the superiority in terms of the number of miners is held by the "Lower Txs" category by a large margin. The lower slope of the graph of this category is also due to the same thing that was mentioned in the previous paragraph:

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  • Higher Txs | 245 miners in 60% Range ---> 21 miners in 100% Range ==> 91.5% decrease
  • Lower Txs | 1475 miners in 60% Range ---> 1229 miners in 100% Range ==> 17.6% decrease

📋 Conclusion

As a summary of the analysis, the following points can be briefly mentioned:

• The average number of transactions per block was considered as an assumption to categorize the blocks of each miner. Transactions lower and higher than this value created the "Lower Transaction Count" and "Higher Transaction Count" categories, respectively.

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• About 32% of all miners tend to mine more than 60% of their blocks with less number of transactions.

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• About 5.3% of all miners tend to mine more than 60% of their blocks with a higher number of transactions.

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• 83.3% of all miners in the "Lower Txs" category mined 100% of their blocks with fewer transactions. These miners make up 26.4% of all miners.

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• 8.57% of all miners in the "Higher Txs" category mined 100% of their blocks with a higher number of transactions. These miners make up 0.45% of all miners.