Logrotate

[Fubero8]

I just found out while browsing backups that the backup for NPM is already over 3 GB, so I was wondering why? And the reason was that the logs folder is over 3 GB, while searching the NPM website I found that the log rotate is done once a week. I've had NPM set up for about half a year now. So I figured that probably the logrotate what should be erasing is not working. What should I do?
I am using NPM with the default sqlite database setup.