Assuming that A2:A12 contains the data, try...

B1:

=MATCH(9.99999999999999E+307,A:A)

B2, confirmed with CONTROL+SHIFT+ENTER, and copied down:

=IF(A1="",IF(A2<"",COUNT(A2:INDEX(A2:INDEX(A:A,$B $1),LOOKUP(9.9999999999
9999E+307,CHOOSE({1,2},$B$1-ROW(B2)+1,MATCH(TRUE,A2:INDEX(A:A,$B$1)="",0)
-1)))),""),"")

Hope this helps!

In article ,
Pluggie wrote:

I have a column with data.
The data consists of incremental numbers:

Column A

1
2
3
4

1
2

1
2
3

What I want to do in column B is count the number of instances of each subset.
Result would look like this:

Column A Column B
4
1
2
3
4
2
1
2
3
1
2
3

The largest subset consists of 9 instances.

I tried reaching a solution using CountIf and nested If-statements, but
without any luck. Anybody have any bright ideas?

by the way 1:
I do have the add-on morefucntions, but didn't recognize a usefull fuction
in there either).

by the way 2: I could replace the numbers with a single character if that
would help simplify this issue.

Thanks in advance for your help.