cpblake,
90th in quant equates to a score of 49.
90th in verbal equates to a score of 40.
However, a 90th in both quant & verbal will give you a score of ~730 = 97th percentage ranking!
The current percentage ranking table is the result of GMAT tests undertook between Jan01 and Dec03 and it became effective on the 1st October 04 for a period of one year. Hence, the pre-october test rush.
Am I right when I say we might be talking about the likes of Stanford and/or MIT here?