Identifying sets of continuous values with a unique ID

[bradynock]

I have data which consists of one column of 0s and 1s (Value column, below). I would like to uniquely identify each continuous "set" of 1s, with a consecutively numbered value (like the example "ID" column below).

Any suggestions on how I might accomplish this?

Value ID
0 0
1 1
1 1
0 0
1 2
1 2
0 0
0 0
1 3
1 3
1 3
0 0
1 4
1 4

[bradynock]

Solved by someone else:
for value in cell A2 and unique ID in cell B2:

=IF(A2=0, 0, IF(A1=1, B1, MAX(B$1:B1) + 1))