Almost 2 million Americans who have been out of work for longer than six months have missed out on extended unemployment benefits since Congress allowed the program to expire in December, according to a new analysis of U.S. Department of Labor data.

In seven states, at least 100,000 unemployed workers didn't get unemployment benefits they would have otherwise received, according to the analysis from the National Employment Law Project, an advocacy group for workers which has lobbied for extending the benefits.

Extended unemployment benefits began during the George W. Bush administration in 2008 as a response to a spike in long-term unemployment during the Great Recession. The extended benefits allowed unemployed workers to collect aid for up to 99 weeks, instead of the normal 26 weeks.

The White House and lawmakers from both sides of the aisle are interested in reinstating the benefits. Four Republicans joined Senate Democrats last month to almost pass an extension. House Speaker John Boehner, R-Ohio, has said he's open to an extension.

The most populous states have the most people who have been affected. But states such as New Jersey and Florida have been hit disproportionately hard because they have high levels of long-term unemployment.

States are largely responsible for regular unemployment benefits, but the federal government covered the cost of the extended benefits. From 2008 through the first half of 2013, Washington spent $252 billion on extended benefits for at least 24 million unemployed Americans.

If the program is not reinstated before April, states and their unemployed workers will have missed out on more than $5 billion in federal money, according to the analysis. Previous analyses have estimated that the cuts could cost as many as 240,000 jobs if they continue through the end of 2014.

People missing benefits include those receiving extended benefits when the program expired in December, as well as those who have exhausted state jobless benefits since then and would have been eligible for extended benefits.