SAN RAMON—Netflix’s video streaming service has surpassed 200 million subscribers for the first time as its expanding line-up of TV series and movies continues to captivate people stuck at home during the ongoing battle against the pandemic. The subscriber milestone highlighted Netflix’s fourth-quarter results released Tuesday. The service added another 8.5 million subscribers during the October-December period, capping Netflix’s biggest year since its inception as a DVD-by-mail service in 1997. Netflix ended the year with nearly 204 million worldwide subscribers. The fourth-quarter gains easily topped the projections of the roughly 6 million additional subscribers projected by Netflix’s own management and Wall Street analysts, even as the company began rolling out price increases of 8 to 13 percent in the United States. Netflix’s stock surged by more than 12 percent extended trading after the latest subscriber numbers came out. After upending the DVD-rental industry, Netflix introduced the then-revolutionary concept of streaming TV …