I made this by using the data from Nintendo's and Sony's shipment sites. Both refer to figures as sales, but of course its sales to stores...which we call shipped. At any rate, the quarters are aligned from launch. The number scale on the top left is total games shipped for the platform divided by number of platforms shipped. For Wii and PS3, Q1 is the three months ending December 31, 2006 and Q8 is the three months ending September 30, 2008. Q9 is expected to come in for both Sony and Nintendo this Thursday (Japan time). The big bump in the pink PS3 line in Q7 is the GTA IV launch mostly as that is the quarter which ended June 30, 2008. For Wii, the dip in the attach rate early on coincides with the early criticisms of Wii, that although it was in a drought it was selling well on Wii Sports, Wii Play, Zelda, and whatever random two other titles people picked up. However, since the quarter ending September 30, 2007 Wii software attach rates have grown steadily largely due to the releases of other essential software (DQ Swords in Japan in July 2007, Guitar Hero in the Americas, Mario & Sonic in Others, Mario Kart worldwide, Wii Fit worldwide, and Brawl worldwide being the major relevant additions in Q4 to Q7).
For DS, Q1 is the three months ending Dec 31 2004, and Q17 is the three months ending Sept 30 2008. After a slow start in selling software, DS is closing in on an attach rate of six games per machines with nearly 100 million machines sold. It sure didn't look like it was headed that way at first, with the attach rate under two games per DS in the first quarter.
Sony doesn't provide shipment data (product sold to stores) for before April 2006, only cumulative production shipments (product in factories), but in the period of April 2006 to September 2008, 2.5 years, the PSP had an attach rate of 4.4 games per PSP, on about 3/4 of all PSPs sold. That suggests the ratio current rests between 3.75 and 5.05, which fits in well with what we know about portables - except in Japan - only an enormous amount of hardware sold will place portable software in the top 10, 20 or whatever because it tends to attach at lower rates than console software.
People are difficult to govern because they have too much knowledge.
When there are more laws, there are more criminals.
- Lao Tzu