Typical Variable on Date

Hello Experts,

I have very strange requirement. I have a coverage date and member ID.

I want to show data "The Number of Individuals Enrolled chart shows the number of individuals enrolled at the end of a given month". I want to plot a line chart and need to show how many people got enrolled with respect to date.

Eg:-

let's say first 0 1 1 1 1 1 1 1 1 1 1 1

if there's another person with coverage start date of 04/05/2014

then 0 1 1 1 1 1 1 1 1 1 2 2

let's say another person with coverage start date 03/05/2014

then 0 1 1 1 1 1 1 1 1 2 3 3

u see what I try to show ?

For this what formulae i need to create ?? ?

Thank you so much in advance.

Best Regards.. Sai