Your reference DID NOT INCLUDE the Postal Service. That fact is stated AT THE TOP OF THE CHART.
You are not using the same numbers.
Just on a lark I decided to look up USPS employment.
from http://www.google.com/url?sa=t&source=web&cd=3&ved=0CCkQFjAC&url=http%3A%2F%2Fwww.usps.com%2Fpostalhistory%2F_pdf%2FEmployees1926to2009.pdf&rct=j&q=USPS%20total%20employment%20by%20year&ei=wpkoTp2QGIOxsAK8nqA7&usg=AFQjCNEdATFrpLtIiF8Xs7WYiawh9iAVpg&sig2=JNZNxR63wjO1p1lKUBOzEQ
(ugly isn’t it? it’s the link to download a pdf)
USPS total employment:
1964 440759
2009 623129
That’s roughly a 40% increase. So with a 58% increase in population, they have increased in productivity. Of course the increase is nothing like that of the private sector, but who’s counting. It is, however, a lot better than other civilian agencies.
Again, however, your claim that federal employment has been static since 1964 is proven to be deceptive.