How to get number of employees per year

Question

Dear,

I have a table called Mst_Employee.Field are

Emp_No
Emp_Name
Emp_JoiningDate
Emp_ResignedDate
Emp_Status


How to get the No. of Employees by Year.
Each year somebody join or resigned.

E.g. Result look like this
Year-----No. of Employees.
2011---- 125
2012-----130
2013-----100

Please help on this
Thanks
Basit.