Should my PFR% be lower at the lower limits?

I play almost exclusively at .25/.50 and .50/$1 limits. My pfr% is only around 4%. I am reluctant to raise pre-flop with hands like JJ and TT at these limits b/c so many players will play any ace, any king, etc., and I know when I'm in against 4-5 players and an ace, king, or queen comes on the flop I'm beat. I always raise with AA and KK, and I almost always raise with QQ, but I'll sometimes limp in in MP or LP with JJ and lower if 3 or more have already limped (I'm actually more likely to raise with JJ in early position if I feel it will narrow the field). Should I be concerned to increase my pre-flop aggression?