The American solar industry employed a record-high 260,077 workers in late 2016, according to a new report by The Solar Foundation.

The Washington, D.C.-based solar advocacy nonprofit has tracked changes in the solar workforce since 2010. Their latest report, released Tuesday, reveals that the industry added 51,215 jobs in 2016 and has had job growth of at least 20 percent for four straight years. It added jobs in 44 out of 50 states last year.

California continued to be the best state for solar employment last year with 100,050 jobs, up 32 percent from 2015. Texas, the third-ranked state for solar job numbers, similarly saw a 34 percent increase to 9,396 in 2016.

Massachusetts, the second-ranked state, and Nevada, the fourth-ranked state, however, experienced dips in their job numbers. So did Delaware, New York, New Jersey and Tennessee. This report provided the state-by-state jobs numbers for 2016 and 2015, but offered little analysis. That will be the focus of a follow-up report slated to be released in March.

“Last year, one out of every 50 new jobs created here in America was a solar job,” Abigail Ross Hopper, president and chief executive of the trade group Solar Energy Industries Association, said in a statement. SEIA is a sponsor of The Solar Foundation’s jobs report. “That’s an incredible finding that proves that solar energy is increasingly becoming a linchpin in America’s economy.”

The growth is largely driven by a boom in solar installations nationwide. In the third quarter of 2016, the latest quarter for which data is available, more than 4 gigawatts of new solar capacity was installed. That’s the most new solar added in the U.S. in a single quarter and represents enough solar to power 6.5 million homes.

Market forces have partly fueled the boom, such as declining costs of solar power. The extension of the federal tax credit for solar companies until 2021, as well as some pro-solar state policies and incentives have also spurred the industry’s growth.

The new report projects the solar industry will add more than 25,000 jobs in 2017, including jobs in installation, manufacturing, sales and distribution, project development and other areas. The report authors also described several potential obstacles to future growth, including declining fossil fuel prices, especially for natural gas, and changes to state policies.

Another example is the possible undoing of the Obama administration’s signature climate rule, called the Clean Power Plan. This rule, finialized in 2015, mandates the decrease of greenhouse emissions from power plants and was expected to help support long-term growth in solar and other clean energy altneratives. But President Donald Trump has promised to revoke the rule and it is already under review by the U.S. Court of Appeals.