before the issue of 2004 labour law, there was no mention of ESB (end of service benifits), from that day onward it's 3 weeks of basic salary for the first 5 years, then 4 weeks for the years after.

example:
worked 12 years from 1998
from 1998 to 2004 upto the company
from 2004 to 2009 (5 years) (1300 / 4)x 3 = 4875.00
from 2009 to 2010 (1 year) = 1300.00

Total 6175.00

plus any leave balance

all above are approximate.