41 for me.
I am curious also to see a poll of age group VS type of RV.
Whenever we camp I can't help but notice that the families with lots of kids have pop-ups and the MH's and big 5th wheels usually are child free. Whenever my DD looks for a new friend to hang out with at the CG, I tell her to ride her bike by the sites with the smaller TT's because thats usually where the younger kids are.
Finances play a big part in this, and by the time you upgrade enough to finally afford to own a MH or 5th wheel, the kids are grown up, and out of the house.
These are just my own general observations and I hope no-one is offended by them.
I myself cannot wait for the day that me and the DH can take our grandchildren out camping in our big ass MH