NEW YORK (MainStreet) — Mitt Romney’s quip last year that he is one of the unemployed may not have been quite so misguided after all. As it turns out, the unemployed have become an increasingly important voting demographic in recent years.

Nearly a third of unemployed Americans voted in the 2010 congressional elections, marking the first time that number has cracked the 30% line since 1986, according to a collection of graphics released by the Census Bureau on Wednesday. Likewise, nearly half of the unemployed voted in the 2008 presidential election, an increase of more than 10 percentage points from the number who voted in 2000.

At the same time, there has been a significant increase in the number of unemployed Americans. There were 15.1 million people out of work in November 2010 when the congressional elections took place compared to 10.3 million two years earlier during the presidential elections. That number has since dipped down a bit to just below 13 million in January of this year, but if voter participation rates remain above 30% in this coming election, it could mean as many as 1 million more unemployed voters than in 2008. That doesn’t even take into account the millions of other potential voters who are unemployed, but are no longer a part of the labor force.

It’s not just the presidential candidates who should be concerned about winning over the growing unemployed voter bloc. Given how little Congress has focused on the unemployed in recent months, incumbents could end up feeling some backlash this election season. Either way, don’t be surprised if you see a few more candidates pull some variation of Romney’s strategy and try to convince the unemployed that they know what they’re going through.

Seth Fiegerman is a staff reporter for MainStreet. You can reach him by email at Seth.Fiegerman@thestreet.com, or follow him on Twitter @sfiegerman.