The information is in the following table.
Percentage 1980-81 1.3 1997-98 3.0 2001-02 3.1 2005-06 3.3 2008-09 estimated out-turn 3.4 Note: DWP total benefit expenditure excludes benefits that are no longer within the remit of DWP. Child benefit and war pensions have been excluded. Source: DWP accounting data