NEW YORK — Broadway ended the 2010-11 season on a box office high, logging a cume of $1.08 billion and robust attendance of 12.53 million, according to the Broadway League.The season ended on a week that saw the majority of individual shows slip somewhat. The highest-profile hits, however, stayed strong. “The Book of Mormon” ($1,168,812) continued to break house records at the Eugene O’Neill Theater while “Spider-Man: Turn Off the Dark” ($1,323,651) also gained a bit of momentum, landing on the third rung of the top 10 behind “Wicked” ($1,732,752) and “The Lion King” ($1,652,879). Another of the spring’s strong sellers, “War Horse” ($910,170), became one of the rare nonmusicals to break the $900,000 mark — an even rarer feat for a play with no movie-star names in the cast. The 21 musicals grossed $18,583,596 for 78.3% of the Broadway total, with attendance of 209,792 at 86.2% capacity and average paid admission of $88.58. The 13 plays grossed $5,155,596 for 21.7% of the Broadway total, with attendance of 68,548 at 74.5% capacity and average paid admission of $75.21. Average paid admission was $85.29 for all shows.