My IPH has virtually flatlined from a lack of LTB gold buildings. And before everyone mentions IPH is meaningless so is Attack and defensive stats. At least for me those two stats continue to rise. There will always be someone to attack and there will always be someone to beat me.
For all my buildings I am at 99% of my potential income. If all my buildings were level 10 I'd have $1.424 billion IPH. As of now my IPH is $1.413.
I suppose this is another factor of where the game is going. Just look at the recycled LTB stats.