What are the percentiles?

I have seen the charts that indicate percentiles for verbal, quantitative, and overall scores. These are useless for setting a goal in each section because if I want to score z on the test, these charts don't allow me to derive what quantitative score (x) and what verbal score (y) I need.

Here is what I want to know: If I get x on the quantitative section, I need to get y on the verbal section to get an overall score of z.

If this information varies from year to year, I would accept this information from whatever year it is most recently available.

This information could be presented in a formula, a table, or an online calculator.

I don't need a ton of data because I am setting a goal of 730-760 so I only need a small corner of an otherwise large table. This is basic information that is necessary for me to set my goals. Where can I find this?