73K Unique Drupal Domains Identified Lists 13 copies
That is result of checking raw list
GSA identified 73K
Xrumer Links database analysis 83K with footprints below
'content="Drupal 7 (http://drupal.org)"'
'<a href="http://drupal'
'<a href="http://www.drupalizing.com"'
'<a href="http://drupal.org">'
"drupal.js"
"http://drupal"
"Drupal.settings"
"Powered by Drupal"
"node.css"
"drupal.css"
Every url contains /node/
If combine these two list you will get 88K unique domains
Price 25$ limited copies 13

GSA identified 73K
Xrumer Links database analysis 83K with footprints below
'content="Drupal 7 (http://drupal.org)"'
'<a href="http://drupal'
'<a href="http://www.drupalizing.com"'
'<a href="http://drupal.org">'
"drupal.js"
"http://drupal"
"Drupal.settings"
"Powered by Drupal"
"node.css"
"drupal.css"
Every url contains /node/
If combine these two list you will get 88K unique domains
Price 25$ limited copies 13

Comments
Scraped and identified that's it.
If you worked with drupal you know average percentage of verified for every 1000 this list should give you pretty same results.