In 2008, of the approximately 1.5 million that took the the SAT ...
about 25,000 got between a 750-800 on CR
About 40,500 got between 750-800 on math
About 22,000 got between 750-800 on Writing.
a 780 in math puts you in the 99%
A 760 in CR puts you in the 99%
A 750 in CW puts in the 99%
On the ACt, in 2008, 1.4 M took the test:
428 scored a 36
2872 scored a 35
6358 scored a 34
10,583 scored a 33
15, 555 scored a 32
A 32 or better puts one in the top 99%
About 90,000 students scored a 750 or better on each SAT section.
If you scored a 32 or better, you are one of about 37,000 who scored in the 99% or better on the ACT. A 34 or better puts you in the top 10,000 students.
It's hard to compare apples to apples - because they do not report the data in the same way. SAT does not give the number of perfect 800's that I can find. Although, keep in mind more students took the SAT.
Not sure if that answers the question - but I've seen so much talk on these boards about the difference, thought this data might actually be helpful.
SAT Data Reports ACT National and State Scores for 2008