I don't remember actual numbers decreasing, but you heard a lot about "white flight" to the suburbs. There was a famous headline concerning the city's financial woes and bankruptcy:
 (President) Ford To New York: Drop Dead

siggy47

Was the city depopulating in the 70's, like it is now?

The most concerning possibility is that they enter a fiscal death spiral like Detroit did during the last financial crisis.

Undisciplined

This Day on SN: August 6

I don't go often. I don't notice a lot of the decay that others do. I have lived there off and on my whole life. It still seems 10 times better than the late 1970s. My god, that could be scary. Watch Scorsese's Tax Driver to get an idea.  