I am using Debian 9 VPS. 512MB RAM

Below is memory usage

Name:  TS.jpg
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I installed it yesterday. We used it for a few hours. It's been 13 hours since installation and at the moment when I took screenshot I was only user online.
It started with something like 68MB and now is as you can see around 100.

Is this normal? I am using other VPS for storage and don't have this problem.