What to look for percentage flop wise?

I just started playing 1/2 Limit on Monday and I noticed that, unlike .25 and .50, sometimes all the "percentage to see flop" figures are in the 40s. Often, I can't even find percentages in the 50s. Should I wait and just try to select a better game when a 50 percenter appears? However, I am wrong in thinking 40s are not lucrative? What's the norm? Anyone know?
Pardon my ignorance and thank you for your time.