Google's primary tag for Google Measurement/Conversion Tracking, Adwords and DoubleClick.
https://support.google.com/adwords/answer/7548399
Analytics and Tracking
Get access to data on 66,301,789 websites that are Global Site Tag Customers. We know of 32,236,010 live websites using Global Site Tag and an additional 34,065,779 sites that used Global Site Tag historically and 3,307,626 websites in the United States.
Get a list of 66,301,789 websites using Global Site Tag which includes location information, hosting data, contact details, 32,236,010 currently live websites and an additional 5,141,743 domains that redirect to sites in this list. 34,065,779 sites that used this technology previouslyand 3,307,626 websites in the United States currently using Global Site Tag.
Countries
Financial
Group
Region