Showdown-- Getting there

[Kevin J]

I really have no mind for math, or statistics and such, which is a great hinderence when it comes to thinking about and improving my poker game. So sorry if this is an incredibly stupid question.

I do understand poker isn't played in a vaccuum and that there are many variables that would factor into the answer I'm looking for, such as opponent types, specific situations, etc. I'm just looking for a rough aproximation...

If you took ALL hands where you voluntarily put $$ in the pot which wound up as a heads-up situation, what percentage should you be getting to showdown? Would anything less than 50% be catastrophically low?

I'm sure this is also very dependent on which types of hands you're willing to play heads-up. I imagine that those willing to defend, steal, or get caught limping with hands like 54s, will not get to showdown nearly as often as someone who selects only hands with some high-card strength in pending short-handed situations.

Lastly, what about AK and AQ? How often should these hands be getting to showdown in heads-up situations? I know some who would say 100% (against a typical or unkown Party player). Do you guys agree with this?