Substract only month and year in c#
===

I have one field in my database that keep the start date of the employee.
And I want to know how many employee that has one year anniversary in this month?
Example, If the employee start work on ` 07/12/2012` so if the current date is `01/12/2013`, It is his/her anniversary.
This is the format string of start date of each employee `07/12/2012`. And I want to compare only the month and the year(not date).

Could any one tell me how to do that? Thanks in advanced.