I served on a NJ board, leading negotiations for the board.so that's my knowledge source. We had a total of 15 steps as I recall, so a new teacher would be at the top level after 15 years of employment. The guide didn't remain static through the years, as the process of contract negotiations would result in a new guide being negotiated between the board and the union.

In negotiations, I worked to keep down the percentage raises at the top of the guide. The whole process would take months, with talk of strikes sometimes. I think my wife came to divorcing me after I came home at 5 am from a long negotiating session. (1 am was more typical.) I had to go to work, that day, and wondered why I was doing this totally unpaid job for the taxpayers of the town. (Al Groh was among them.)

Edit add. The teachers union always wanted to reduce the number of steps for obvious reasons. There was one township in NJ that I was aware of that had 30 steps in their guide.
[Post edited by NJHoo at 01/15/2018 5:14PM]