Allow? I'm sorry, but the Commonwealth of Pennsylvania does not allow me to do anything. It may prohibit me from doing certain things, but it doesn't have the power or authority to allow me to do anything - I do such of my own free will. That which is not specifically prohibited by law is legal.
Our state's consititution,one ofthe oldest in the country, guarantees our right to keep and bear arms. Based on that right to bear arms, our state supreme court has ruled that open carry is legal throughout the Commonwealth. That being the case, I open carry most of the time. And we don't have to worry about .30-06 signs, or 7.62 signs, or any signs at all except for "No Trespassing" signs - they have no legal standing.
Statistics? Well, seeing as how 44 states do not prohibit open carry, the question becomes how do the remaining 6 compare when it comes to crime rates, and is such relevant? That may be as close as you're going to get to so-called open carry statistics.