If you have repeatedly turned on the iPad, because may be it has gone to sleep, you could have higher percentage than normal. If you access a lot of widgets they will use power, as will Notifications.
Seems excessive - just checked my iPad Air 2 (on iOS 10.3 - might want to tell us your iOS?) and for the past 7 days, my reading for 'Home & Lock Screen' is just 3%. You've already been given great advice; also, check this OSXDaily Article for more suggestions; finally, check what your radios are doing when the iPad is sleeping - good luck and please let us know what seemed to help. Dave
With background refresh on, such Apps as News, Weather etc will check for updates periodically. Otherwise, when you next open the App they will just update then.