Yesterday I reported a fumble in how I analyzed the 2015 executive budget, which appeared to show a substantial increase in library funding over what the four library systems had to spend in the current 2014 fiscal year.

This made it look like the research libraries, New York Public Library, Brooklyn Public Library and Queens Borough Public Library were slated to receive boosts of 20 percent or more. Given all the reporting by Suzanne Travers on the amazing work libraries are doing, that was exciting news.

But it turns out the city actually spent more in 2014 than those budget documents indicate, because a portion of the library systems’ 2014 budgets was prepaid in 2013. This is what the city does when it has a surplus: rolls it into the next year by prepaying expenses. In 2013, libraries got some of the extra dough.

When you add those payments in, the numbers from this year and in Mayor de Blasio’s proposed budget are almost identical: