How do increase how much historical stats are kept

Hello,
I have a temperature probe service
when i look at the “Service Log Entries” there appears only 1 aday.
i know the device gets pinged more than once a day (actually every 5 minutes)
I can i save this historical data?
thanks
randy

It’s my understanding that these are compressed and then kept indefinably. Any simplification of the raw logs is done by the web interface.