Almost half of all K-12 students in the United States are at schools that have resumed five-day-a-week, in-person instruction, according to updated figures from a tracking organization. Up from about 47 percent a week earlier, roughly 49 percent of U.S. primary and secondary students are attending so-called traditional schools, Burbio said on March 14. At the same time, about 21 percent of students are attending schools that continue only offering virtual classes, down about 3 percent, while 30 percent attend “hybrid” schools, or schools that offer in-person classes but not five days a week. The peak of students attending virtual-only schools took place on Labor Day 2020, with 62 percent of students having no option of taking physical classes. The figure dropped to just under 37 percent by early November last year before rising to 55 percent in January. Shortly after, another drop started. The 21 percent is a new …