a quick search came up with this. 2004 is 10 years after the launch of ps1. The market has grown a lot since then, and wii will sell a lot more than the ps1.
2004 - 5,000 / 2.54 million
2003 - 34,000 / 4,14 million
2002 - 233,000 / 5.7 million
currently playing: Skyward Sword, Mario Sunshine, Xenoblade Chronicles X