Source: US Census. The median household income in the US is $50,502. This is some extremely useful data given that it is exploring over 114 million US households. If you want to know how most Americans are living this is a good figure to base your assumptions.
The myth that you have to wait 30 minutes or even an hour until you can swim after eating has been conventional wisdom for some time. The simple fact is, however, that swimming on a full stomach does not significantly impact your ability to swim.
Suppose you can swim for 20 minutes, with generous breaks at each end of the pool. You should plan on swimming for 30 minutes, then, so that your actual exercise time (as opposed to rest time) ends up around 20 minutes. To begin, commit yourself to three times a week, 30 minutes per workout.