Vibration levels increasing over time

Recently started to fly my drone again after a few months of being unable to fly.
So I had a look at the .bin file and discovered the vibration levels have increased. Yet no changes been made to drone, nothing appears to have worked itself loose or any other explanation found.
After comparing current vibration levels with those just after the notch filter was set just a year ago it appears there is a steady increase of vibrations levels occurring.
Has anyone any idea as to why?

(Oldest file just weeks after setting notch filter)
https://drive.google.com/drive/folders/1aoRXm3bd4WdVn9b4tictfrrl62JOerT1?usp=sharing