Yes and no.
It does keep stats for as long as the device is connected, aggregated.
You can use Tools / Graphing but it can be a load on local resources.
If you want more detailed info, you need to look at other options:
Splunk: http://forum.mikrotik.com/t/tool-using-splunk-to-analyse-mikrotik-logs-4-0-graphing-everything/153043/1
Kid control (someone here made a script to use Kid Control to collect stats etc. Maybe you can find it if you search a bit, I couldn’t find it right away)
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