Primary buyers being OEMs I presume.
Probably a good chunk, but I know lots of retail packages have sold through distribution channels.
Assuming an average price of $30 per OS (OEM and retail), we’re looking at $4.5 billion in sales of Windows 7 alone, in 8 months. That means close to $7 billion in sales in the first year, at the current rate. That’s a huge amount of revenue from just the new OS (they’re still selling lots of XP licenses, as well).