Maybe five, ten, twenty years ago traffic signal buttons in NYC were an everyday sight, but they are increasingly further and fewer between. Taking the article's 100 functioning + 1000 non-functioning buttons at face value, combined with the fact that there are ~12,000 signalized intersections in NYC [1], means that it is likely that less than 2-5% of the crosswalks in NYC have buttons.

A fully equipped traditional "+" shaped intersection would have 4 crosswalks and 8 buttons, so 1100/(12000 * 2 to 8) = 1% to 5% of crosswalks could have buttons.

NYC gets a lot of grief for decrepit infrastructure, but this is an area where they have actually started to remove the unused stuff.

[1] http://www.nyc.gov/html/dot/html/infrastructure/signals.shtm...