No Market Share movement for Google Checkout yet sorry.
Get a list of 48,881 websites using Google Checkout which includes location information, hosting data, contact details, 37,572 currently live websites
which includes 30,504 domains that redirect to sites in the list. 41,813 sites that used this technology previously and 5,671 websites in the United States currently using Google Checkout.
Distribution of locations of all Google Checkout customers we've ever tracked.