Attendance
noun, verbal noun
The people who exit their seats at the end of the show are the number of people who showed up, not counting empty seats. This is the true attendance.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. Just note the しゅつ gets changed to しゅっ, as many つs do in this situation.
申しわけありませんが、出席は不定期になると思います。
I'm afraid that my attendance will probably be irregular.
コウイチのたん生日パーティーには、出席しない予定です。
I'm not planning to attend Koichi's birthday party.
別の便に乗せていただけますか？どうしても、主要国首脳会議に出席しなくてはならないんです。
Could you put me on another flight? I really have to attend the annual G8 leaders summit.