From the latest and last ever special issue on Gundam by Nikkei BP.
Yearly Gundam Sales
1999 - 21.2 billion yen
2000 - 24.6 billion yen
2001 - 39.3 billion yen
2002 - 45.2 billion yen
2003 - 54.2 billion yen
2004 - 42.8 billion yen
2005 - 51.8 billion yen
2006 - 57 billion yen
Top Selling Individual Gundam Games
1) Mobile Suit Gundam Federation vs Zeon DX - 950,000 copies
2) SD Gundam SD Sengokuden Kunitori Monogatari - 920,000 copies
3) SD Gundam G Generation - 730,000 copies
4) SD Gundam 2 Capsule Senki - 660,000 copies
5) Mobile Suit Gundam Encounters in Space - 640,000 copies
6) Mobile Suit Zeta Gundam AEUG vs Titans - 630,000 copies
7) SD Gundam G Generation NEO - 590 copies
SD Gundam Knight Gundam Story - 580,000 copies
9) Mobile Suit Zeta Gundam Zero Scramble - 570,000 copies
10) SD Gundam G Generaion 0 - 570,000 copies
Top Selling Gundam Series Games
1) SD Gundam - 10,510,000 copies
2) MSG - 7,660,000 copies
3) Zeta - 1,830,000 copies
4) SEED - 1,760,000 copies
5) MSG Side Stories - 1,380,000 copies
6) CCA - 470,000 copies
7) F91 - 450,000 copies
Wing - 230,000 copies
9) G Gundam - 180,000 copies
10) V Gundam - 70,000 copies
Top Selling Gunpla MS (based on HG & MG sales from 1995-Sept 2006)
1) RX-78-2 Gundam
2) Zeta Gundam
3) Char Zaku II
4) Hyaku Shiki
5) Zaku II
6) Guncannon
7) Qubeley
GP01
9) Gundam Mk-II
10) Gouf
Frm Gunota