Default Problem on Charging the battery

Hello,

I faced a problem about 2 weeks ago till now.

It is When try to charging my HTC ONE, when the battery is about 90%, 90% to 100% gone very fast and the LED shows green. But when unplugged and plugged the charger again, percentage of battery dropped to about 90% - 91% and it charged fast to 100% again.

When I let its remain on green status and plugged, after about 10 minute, my device charged fully (I tested it again: first unplugged the charger then re-plugged. Battery status dropped to 99% and after 30 sec it shows fully charged)

What is the exact problem?

Thanks