Note this important comment in prior string:
Secondly, don't be fooled by the federal locality percentages. They are not built off of a national index of 100. Every federal locality in the 48 connected states gets at least 14.16% (see schedule for "Rest of the United States"). So the geographic differential from the lowest area (14.16%) to the highest area San Francisco (35.15%) is really 20.99%. The federal locality premiums would be even smaller if compared to a national average index of 100 if such a thing was actually calculated by the feds.
Another source: http://www.bls.gov/oes/current/oessrcst.htm