The Washington Post (possibly more reliable link here) does not use phony documents, but the thrust of the story, including the headline "More U.S. families struggle to stay on track" is at variance with the facts that they present. The key chart, which is included on the jump page in an obscure way and never discussed in the article, reports on the change in the distribution of income, using 2003 dollars (I converted the data to tabular format).
Percent of Households
$75K and up
$50K - $75K
$35K - $50K
$15K - $35K
The article emphasizes that the middle has shrunk, from 22.3 percent of households to 15.0 percent. What it does not point out is that the two categories below the middle also have shrunk, from 52.8 percent of households to 40.9 percent. Adjusting for inflation, the percentage of households with incomes over $50,000 has climbed from 24.9 percent in 1967 to 44.1 percent in 2003.
The article's claim that it has become harder to stay in the income range of $35,000 to $50,000 is correct, if what you mean by "harder to stay" is that it has become difficult to avoid being squeezed up into a higher category.