Ubisoft have released some sales numbers of their most popular active franchises:
Assassin's Creed: 73 million
Just Dance: 48 million
Tom Clancy's Splinter Cell: 30 million
Tom Clancy's Rainbow Six: 26 million
Tom Clancy's Ghost Recon: 25 million
Petz: 24 million
Rayman: 25 million
Imagine: 21 million
Prince of Persia: 20 million
Driver: 19 million
Far Cry: 18 million
Rayman Raving Rabbids: 14 million
The Settlers: 10 million
The Experience: 9 million
Anno: 5 million
Your Shape: 3 million
No word on exactly how up to date the numbers are, but we assume they're fairly up to date.