I have a solution that will work if you don't mind adding a couple of columns, one immediately to the left of the source column (D) and one immediately to the left of your results column (currently column A).

(This also assumes that the identifying characteristic of a "good" value is one in which the 3rd character is "/").

The column next to column D should contain the following formula:

C1: If(mid(D1,3,1)="/",1,0)

C2: If(mid(D2,3,1)="/",int(C1)+1,C1+0.001)

Copy C2 down the rest of the list.

Now insert a new column to the left of column A. Start A1 with the value 1. Fill the column by series for as many rows as you think you'll ever need (i.e. in your example fill from 1 to 14.)

(Columns C & D are now D & E.)

In the new column B, enter a vlookup formula as follows:

=vlookup(A1,D$1:E$14,2,0)

and copy this down for as many rows as necessary.

I've used this method in many situations, creating a kind of "custom index". I hope it works for you.