Deb, I agree with what you said. SO MUCH of this is affected by age, health, and whether or not you are past menopause. I've talked to my mother-in-law about this (she's in her early sixties), and she and all her friends of about the same age are suddenly having "reproductive system issues" that are new and alarming. We've had a giggle about it, and I know it's coming down the road one day for me too.
I pay no attention to the so-called national averages, other than idle curiosity. I don't measure myself against them. My level of interest is what it is. There are times I do it to be accommodating, but I wouldn't knock myself out trying to "put out" for a man who wanted it many times a week because at that point, I don't think I'd be enjoying myself much. I AM NOT a warm place to...uh...I'll let you finish that sentence in your head.
And anyway, they're averages for a reason. They include the rabbits and the nuns! Some people actually want it multiple times a week, some do it way more than they want to in order to please their spouses, and some couples work out a happy compromise (since there's usually a discrepancy in levels of interest). It's whatever works for the couple, although I think it is true that sex is *usually* an important part of the glue that holds a romantic relationship together. I guess for some couples, sex is like krazy glue -- a little goes a long way -- and for others, it's the Elmer's stuff that you need copious amounts of or else it'll all fall apart, lol.