Tax liability regarding prbs

Hi All,
The Following is the PRBS Break up

Financial Year                Amount of Contribution

  2006-07-                           6,332.40

  2007-08-                          25,947.09

  2008-09-                           29,026.80

  2009-10-                           33,049

  2010-11-                           38,583

  2011-12-                           44,338

  2012-13-                           49,767

I Think Up to FY:2009-10 it is Exempted from tax liability.From fy:2010-11 to 2012-13 it is exempt up to 1 lakh.My Doubt is 1 lakh of exemption is for each year are it is a cumulative exemption.

Thanks in Advance.