Increment count if not duplicate

I am trying to make a function in Excel 2013 that increments the count if there is not a duplicate, but rather repeats the number if there is a duplicate, and skipps if there is a blank entry. I have Google this with no luck, anyways here is my example; any help would be appreciated.

B .......................C
1 City ...................Number
2 Alabaster ................1
3 Alabaster ................1
4 Alabaster ................1
5 Albertville ................2
6 Albertville ................2
7
8 Athens ...............3
9 Auburn ..................4
10 Dothan ..................5
11 Dothan ..................5
12 Mobile ...................6