in 2009 each computer mined a block

you can look at the first 1000 blocks (jan 9- jan19) so average 100 blocks a day
you can look at the next 2016 blocks (upto 3016) (jan19- feb4) is 17 days so average 118 blocks a day
and so on
and so on

then you can look at the "patoshi nonce count" data, to see which blocks got solved in sequences (meaning same computer)
and you can see how many computers were involved over time