A new report says a United States government program for foreign students has been expanding in recent years. The government’s Optional Practical Training, or OPT program was set up to help foreign students graduating from American colleges and universities. It gives them a chance to stay in the country for temporary employment after they complete their studies. The report is from the Washington-based Pew Research Center. It notes that many foreign students take classes in science, technology, engineering and mathematics. These four subjects are known by a single term: STEM. The center noted that, under OPT, the number of foreign students graduating and working in STEM fields rose 400 percent between 2008 and 2016.