Charter schools are beating other New York City schools on math tests, the latest state test results show.

This year, 74% of city charter students scored proficient on the state math test, up from 66% last year, a review of state data by a procharter group, the New York City Center for Charter School Excellence, found. Just 65% of students citywide scored as well this year, up from 57% last year.

Mayor Bloomberg and his schools chancellor, Joel Klein, applauded the results. “The charter school model is working in New York City,” Mr. Klein said in a statement.

Charter schools also outperformed the city schools on reading tests this year — but by a smaller margin than was originally clear from state Department of Education reports. In May, The New York Sun reported that 61% of charter students met state standards. The city charter group confirmed that figure in a newsletter the same month.

But the center changed its calculation to 57% yesterday. The center attributed the adjustment to a “technical glitch” by the state department, which excluded special education students from city charter schools’ averages — and added their scores to district averages instead. The center’s statement said data posted on the state department’s web site remains “incomplete.”

The group had mentioned it was investigating concerns about the counting of special education students in its May newsletter.

A spokesman for the state education department could not immediately confirm the error yesterday.

If correct, the new figure means charters’ reading scores improved just one percentage point versus last year, figures reported by the city center in May and calculated by the Sun show.

Charter schools are publicly funded but privately run. This year, Governor Spitzer raised the number of allowed charters to 200 from 100.