Currently, the apt_all plugin gets the stats from a state file, updated
periodically by a cron job. I would guess this is to allow it to be run
as a non-root user when called via munin?

Since version 0.7.22, apt has supported running the '--simulate' option
as a regular user. It warns that the output may not be 100% accurate
since it doesn't perform logging, but it should be good enough for
munin's purpose.

It would be nice if the plugin could use 'apt-get --simulate upgrade' to
gather the stats, to prevent the graph from lagging behind reality;
currently the graph will only be updated after an upgrade once the cron
job runs again.