On our trip in May there were 4 families, 5 couples, 1 Mother/Daughter, 1 Sister/Sister, and 1 lone traveler. I would expect the time of year will probably influence the demographics, with June/July/August to have more families than other times.
I don't think it really matters if you have kids or not.
I guess in general the families did have a tendency to go their own way during the free times, whereas the others (couples, etc.) tended to form little groups and do stuff together (dinner, boat tours, palace tours, etc.).
I also have to echo the comments about how well behaved the kids were on our trip.