Drupal download statistics are captured but not posted on Drupal.org yet. Please note, that Drupal targets developers and developers overwhelmingly prefer to get their code via a revision control systems, which for Drupal is Git. The download numbers will not reflect getting Drupal from Git.
The hold up there is these per-month totals are currently stored in MongoDB; the Drupal.org database only has the aggregate counts per release (this is in the project_release_file.downloads column) which is not very useful. Tracking status on this at http://drupal.org/node/32124.
Members of the drupal.org infrastructure team can SSH these statistics by accessing util.drupal.org to find the raw report.
~bdragon/download-report drupal
That'll print a table like:
-bash-3.2$ ~bdragon/download-report drupal
-- drupal (3060) --
Month 4.0.x 4.1.x 4.2.x 4.3.x 4.4.x 4.5.x 4.6.x 4.7.x 5.x 6.x 7.x 8.x
Jan 2009 0 0 0 0 0 58 172 3,442 45,169 171,654 4,812 0
Feb 2009 3 3 3 10 12 89 166 2,907 27,145 136,994 2,262 0
Mar 2009 7 7 7 14 16 33 114 3,776 31,727 186,791 2,998 0
Apr 2009 16 13 12 36 45 96 221 3,782 35,611 150,626 3,036 0
May 2009 11 7 7 21 20 35 136 3,352 31,759 209,779 3,100 0
Jun 2009 16 15 14 35 41 106 172 3,861 28,676 248,427 3,442 0
Jul 2009 5 5 5 12 13 35 76 2,038 14,519 99,562 1,655 0
Aug 2009 11 8 10 30 34 76 161 3,674 21,170 137,224 4,179 0
Sep 2009 12 10 8 26 35 80 148 3,691 24,164 191,922 12,241 0
Oct 2009 11 11 11 37 46 99 192 3,862 33,407 187,630 6,240 0
Nov 2009 7 5 5 14 17 49 124 2,479 19,161 148,692 6,771 0
Dec 2009 7 7 8 17 22 63 128 1,212 14,344 152,921 5,623 0
Jan 2010 16 8 10 26 35 97 174 1,342 14,058 149,034 15,208 0
Feb 2010 5 4 6 10 13 23 64 1,194 12,792 126,880 12,760 0
Mar 2010 5 5 5 13 11 35 83 1,131 15,455 189,280 45,652 0
Apr 2010 5 4 5 13 17 40 99 3,104 16,719 162,769 16,098 0
May 2010 12 6 7 19 22 47 99 3,796 15,621 146,060 17,418 0
Jun 2010 9 5 4 16 19 57 92 3,671 10,800 141,163 11,889 0
Jul 2010 5 6 5 15 19 45 82 3,728 9,958 124,683 14,470 0
Aug 2010 10 8 13 25 32 72 160 3,915 12,548 179,613 14,084 0
Sep 2010 1 0 1 1 1 2 287 3,615 11,439 121,544 13,121 0
Oct 2010 2 1 4 4 5 12 330 4,292 13,797 138,327 28,124 0
Nov 2010 7 4 7 17 22 56 284 4,200 13,939 136,676 25,541 0
Dec 2010 7 6 5 16 16 41 247 3,560 9,645 144,557 44,745 0
Jan 2011 59 7 114 76 73 303 407 2,318 6,018 103,328 175,841 0
Feb 2011 11 5 8 10 11 29 166 1,172 3,659 81,257 142,383 0
Mar 2011 9 5 6 31 18 46 106 952 3,919 85,723 148,974 356
Apr 2011 6 2 5 11 10 26 82 810 3,300 63,666 109,079 447
May 2011 15 4 9 13 17 52 91 742 3,460 85,477 133,432 515
Jun 2011 7 5 5 16 17 36 83 856 2,823 90,037 138,339 532
Jul 2011 12 8 11 29 34 78 130 799 2,543 56,757 130,721 477
Aug 2011 3 3 3 13 9 20 60 726 1,367 43,217 111,717 358
Sep 2011 4 2 1 7 6 16 99 821 1,370 43,655 123,354 415
Oct 2011 15 13 14 39 52 118 215 949 1,657 37,461 107,436 453
Nov 2011 5 5 5 17 17 40 91 535 1,027 26,749 82,881 347
Total 336 207 343 689 777 2,110 5,341 86,304 514,766 4,500,135 1,719,626 3,900
G.Total 6,834,534