If am not mistaken...
more than 1 yr - its 3/4 of a month's basic
1 yr and less than 5 yrs - its 1 month basic salary
5 yrs and less than 10 yrs - its 1.5 month basic
and 10 yrs and above its its - 2 months basic salry per yr...

I dunno if local companies follow this...govt and international companies follow this law..