iPhone 6(S)/Plus Battery problems?

[Ratatapa]

So I have an Iphone 6S (day 1) and i had to change the battery in October 2016. But now i feel like the battery empties faster. Here are some screen shots i took, is this normal? It's hard to say how fast it discharge, but is it normal that it seems 7% after 1.5year?

Tanks

https://i.imgur.com/X3nPue9.png
https://i.imgur.com/bgDxoLv.png
https://i.imgur.com/h6W94b1.png