Hello, I am trying to fill a column with a number series starting with 1 whenever a value changes in the adjacent column. So for instance I am trying to do something like this :

87 1
87 2
87 3
88 1
88 2
88 3
88 4
89 1
89 2
90 1
91 2
92 1
92 2
92 3
92 4
92 5
92 6

Any help would be greatly appreciated, thanks!