Since 1921, Congress has set hard numerical caps for most types of immigrants coming to the United States on green cards. They have always included uncapped exceptions to green cards for most spouses and minor children of American citizens, but other family-based green card categories and economic or employment-based green cards have had numerical caps based on the category, country of origin, or both since 1921.

During that time, Congress allocated 25,294,990 green cards under the numerically-limited green cards categories, but the government only issued 20,567,754 green cards that counted against those caps. Recapturing all those historically unused green cards, minus the 180,000 green cards recaptured in other legislation, would yield 4,547,236 additional green cards – enough to reduce the entire current green card backlog by 96 percent.

We counted the number of green cards issued annually against the number of green cards available in the capped categories in the historical INS and USCIS documents back to 1922. That year was the first full year in which numerical quotas were applied. We then added the roughly 2.7 million green cards issued after the 1986 Immigration Reform and Control Act amnesty because they were erroneously counted against the numerically capped categories in some years. Occasionally, more green cards were issued in the capped categories than were allowed, so we subtracted them from the total number that can be recaptured. We also subtracted the 130,000 and 50,000 green cards recaptured in the 2000 American Competitiveness in the 21^st Century Act and the 2005 REAL ID Act, respectively.

In 72 of the 96 years from 1922 through 2017, when we have data on the number of green cards issued and when the numerical caps were fully in place, the U.S. government has issued fewer green cards than were allocated under the cap. The Great Depression and World War II saw the greatest number of unused green cards – about 1.9 million.

Previous bipartisan bills introduced in recent years have sought to recapture some green cards, but they only go back to the implementation of the Immigration Act of 1990. This proposed recapture is bolder as it goes back to the implementation of the first green card quotas in 1921. As a justification to reduce the green card backlog to a manageable level or to clear it out before replacing the current system as part of comprehensive immigration reform, recapturing over 4.5 million unused green cards from the past would reduce many of the most maddening aspects of the current immigration system.

Special thanks to Sofia Ocampo-Morales for her research for this blog post.