I know this is an old post, so moderator feel free to delete it if you find it inappropriate, but the question asked wasn't answered. I figured this would be useful if someone found this via google.

Yes a 700 changes over time, and does not mean the same thing as when the test was taken.

Below is a table taken from my website, where I have a post comparing percentiles over the last 30 years. Here is what it looks like for a 700 over time.

XXX -|2011|-|2009|-|2008|-|2005|-|1997|-|1996|-|1994|-|1978|
700 -|0.9 |-| 0.9|-| 0.9|-|0.92|-|0.97|-|0.97|-|0.98|-|0.99|

So a 700 in 1978 would have been in the 99th percentile, in 94 it would have been a 98th percentile, etc.

What is most interesting is that there is actually a change in the percentile within a 5 year period, which is the length of time your score is valid for.

You will notice on most admissions applications that you are asked to enter your score and the percentile. It is important that you report this on your original score report. If you retrieve your score report at a later date the percentiles will change to reflect the current percentiles not what they were when you took your exam. So, using the 700 as an example, from 2005 to 2008 it would have made a difference of 2 percentile. Another way to think of it is that a 700 in 2005 was the same as a 710 in 2008. If you had scored two scores, a 700 and a 710, would you report the 700? This is the same scenario.

(Sorry the table was a little funky. HTML was disabled so I wasn't able to get nice formatting.)