Running Count

To apply running count firstly sort  the data on the basis of which you want to apply the countif formula eg. Like below data is firstly sorted on basis of city and after that apply countif formula.

A1  City       Formula                     Ans
A2  Delhi     =countif($a2$:a2,a2)  1
A3  Delhi     =countif($a2$:a3,a3)  2
A4  Delhi     =countif($a2$:a4,a4)  3
A5  Mumbai=countif($a2$:a5,a5)  4
A6  Mumbai=countif($a2$:a6,a6)  5