No Market Share movement for Drupal Version 5.1x yet sorry.
Get a list of 772 websites using Drupal Version 5.1x which includes location information, hosting data, contact details, 192 currently live websites
which includes 27 domains that redirect to sites in the list. 607 sites that used this technology previously and 77 websites in the United States currently using Drupal Version 5.1x.
Distribution of locations of all Drupal Version 5.1x customers we've ever tracked.