Yes, I think you're right. WA does cite the same report as its source, but appears to have different figures.

Looks like for CA (before inflation adjustment in parens):

1992: $7684 ($4697), 2010: $9870 ($9375) = ~28%

And NY:

1992: $12267 ($7498), 2010: $19127 ($18618) = ~55%

EDIT: re-calculated using data directly from US Census Bureau (http://www.census.gov/govs/school/).