wouldn't be too difficult m8.
You have all the software sales, just take the SW sold by the year and divide it by the number of consoles sold.

Then create a total

Then do the same for lifetime, including last 4 months of each year. Use the average attach rate that you got and subtract the average attach rate for the first year of sales. Soon you will be able to predict how many SW sales will occur any month of the year.

Well am busy collecting the monthly hardware sales now,
 just capturing a few every so often between tasks at work ;)

EDIT: And its up, take a look at this thread

Data has been update to October

Will update the second thread shortly.

Data has been updated to end of November. Graphs to be updated in the other thread soon

PS360 is doing veru well!

Wow at the wii...sure its dropping HW and SW sales but still ahead of the competition by a lot and i mean by a lot....

Data has been updated till December. Interestingly the Wii managed to jump from a -2.5% software sales to last year to a positive 3.5%.
However 360 dropped from 3.9% to 0.7% and PS3 improved from 13.6% to 13.9%

I have updated the other post as well and will post there now

Skipped a month but here is the update till February

I have included the sales relative to toatal year sales, interesting rise in software sales for the PS3 and 360 from last year thanks to strong SW releases.

EDIT: Later this month I will start looking into adding the graph which includes tracking Life of HW.

As with the sister thread decoded to update after a hiatus

These are total SW sales for each console up to end of August 10:

Which relate to a growth in % over the previous year to:

 With the sales relative to total year software sales

Thanks for updating the thread.