Attrition Rate Formula

Hi All,
Greetings!!
Can anybody please help me in calculating the attrition rate. I am not able to figure out the actual formula. Tried Google as well but too many formulae & can't make out which is the actual one.
Thanks,
Axita

Opening balance
No. of Emp Joined
No. of Emp Left
Closing Balance : Opening balance + No. of Emp Joined - No. of Emp Left
Avg. Head Count : Opening balance + Closing Balance / 2
Attrition % : No. of Emp Left / Avg. Head Count * 100

Hi Axita,
This one can also help you.......
Resignees/Closing Headcount
closing Headcount= Opening Headcount+New Joinees-Resignees
Check out

Opening balance : 817
No. of Emp Joined : 35
No. of Emp Left : 19
Closing Balance : 833
Avg. Head Count : 825
Attrition % : 2.30
Formula :
= Opening balance (817) + No. of Emp Joined (35) - No. of Emp Left (19)
= Closing Balance (833)
= Opening balance (817) + Closing Balance (833) / 2
= Avg. Head Count (825)
= No. of Emp Left (19) / Avg. Head Count (825) * 100
= Attrition % (2.30)
Now, the Attrition Rate is 2.30%.