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.
If swimming 100 yards is not yet possible go to Zero to 700 If you're having trouble sticking to freestyle (crawl) see green note below. Young or old, fit or not, six weeks seems to be the most common length of time it takes to be able to swim a mile without stopping for rest. It requires three times per week and the willingness to be somewhat uncomfortable while stretching your aerobic capability.