unusual current drain frm SRS

I'm driving a DC5, I have bought an optima battery 2 yrs ago and it went dead, i was told by the guy in autobarn that it should last at least 5 years. using an multimeter i found out the currect drain when my car is off is 300mA. by taking each individual fuse in the fusebox i found out SRS actually drains about 300mA when my engine is off. Is the drain unusual? looking at other forums, it should be around 50mA only. can someone confirm their SRS drain with me? Thanks