in EP I will sometimes open limp 22-99. the top end of the scale i will raise quite a lot. and the bottom end of the scale i will limp quite a lot. not sure of exact percentages.

i play $50NL at pokerroom.
i think raising 22 utg at a FR table would make you less money then limping it.

i think you have a big leak if you say you will never open limp. poker is a situational game. there are times where there is just no value in raising. if you are playing at weak low stakes tables - you can stack someone nearly as easily with a set if the pot has been raised pf or not. and a lot of the tables are passive and a high percentage of the time you will see a flop without a raise behind you.

there must be tables where you have limped utg and if you are unwilling to do so - because of principle - i believe you have a leak in your game. poker is situational and you need to adapt. and that means that sometimes you should open limp hands.

if you are at a loose/weak table and you know a raise will be called by a lot of players and if you limp - most of the time there will not be a raise. and you have the better of it pf and think you'll get paid off big if you hit a flush, 2p, a straight, etc.
then it is a good idea to play some weaker holdings like QJs or J9s.