In the 2015-16 season, the Met took in 66 percent of its potential capacity. Some numbers are improving a bit more substantially: The company’s paid attendance rate, which includes discounted tickets, rose to 75 percent this season from 72 percent in 2015-16. And the company said it attracted 80,000 new ticket buyers this season, up from 74,000 the year before. The challenge is turning those newcomers into regulars.