The median household income in the US in 2008 was $52,029. Probably with health insurance, but still. If $60k is pretty tight, most of the country has it pretty bad.
$60k is claimed to be tight for raising a family of 4. You're looking at households, which are not the same thing at all.
According to the table at http://www.infoplease.com/ipa/A0884238.html (which claims to be using census data; I tried digging through the census website for this information but actually finding it there is a pain) as of a few years ago 27% of households had 1 person. 33% of households had 2 people. You will note that adds up to 60% of the households. So the median household size is 2.
Households with at least 4 people (the ones that $60k is claimed to be tight for) make up, according to the same table, about 23% of households.
It would be interesting to look at the income distribution for such households, since _that_'s what would be relevant to the concern you're raising; I would expect their median household income to be somewhat faster than $52k, though possibly not a huge amount more. If you can figure out how to get this data from the census website, I'd be really interested.
http://quickfacts.census.gov/qfd/states/00000.html