By what algorithm do servers get into the ad unit?

The first 10 servers in the global ranking will be promoted in the ad unit.

The server that occupies the first position is always in the ad unit and is also highlighted.

After the first server, two more servers from positions 2 to 10 are displayed. To select 2 servers out of 9, the following algorithm is used.
Imagine 100 boxes in which we put the 9 servers, and then randomly select two boxes. Since we have 9 servers and 100 boxes, we will put the same servers in multiple boxes. In order for the server to have a better chance of reaching position 2, it is located in 49 boxes, ie the chance of getting into advertising is 49%. The lower the position of the server, the less likely it is to be found in these boxes.

What are the chances of getting into advertising depending on the position?

The approximate number of server ad impressions is displayed based on the average number of page impressions for 30 days in the last 12 months. Now it is about 520.000 (this is not an accurate and not guaranteed figure, as it is impossible to predict the attendance of the site accurately).

1. Position: 100% = 520.000 impressions
2. Position: 98%  = 509.600 impressions
3. Position: 40% = 208.000 impressions
4. Position: 20% = 104.000 impressions
5. Position: 12% = 62.400 impressions
6. Position: 10% = 52.000 impressions
7. Position: 8% = 41.600 impressions
8. Position: 6% = 31.200 impressions
9. Position: 4% = 20.800 impressions
10. Position: 2% = 10.400 impressions