Washington Post median income for Maryland: $52,868
Sure it says Election 2006, but its from 2000 Census in tiny print at the very bottom. My bad.
Three-Year-Average Median Household Income by State: 2003-2005
Maryland $58,347
In another chart on the same wikipedia page, Maryland has a median income of US$ 63,082, based on 2006 dollars.
Clearly the economy has been doing well in Maryland.
So now, I don't know if $45,000-$50,000 would put you in the middle quintile in Maryland.
There was also the point of cost of living:
Median household income comparison of two states based on PPP.
California US$ 55,000
West Virgina US$ 33,000
That means, even after cost of living is factored out, Californians still make way more than West Virginians. I will see if I can find more on that, especially in regards to Maryland, but supposedly California is a very high cost state.
p.s. There is also a figure for median income for a family of six in Maryland that is $94,017 but I think that just means those who choose to have that many children are already making more money. Because normally having more kids doesn't help increase your income.
Another census information says the median income for self-employed no-incorporated workers is only 37,000...that's way below the median income. I guess working for a big faceless corporation is much better paying.

