This implies, that we really have no idea how long they have been running, as the Tomcat work directory may have been cleared at some point in time. We know it was cleared on 2015-07-28, but we do not maintain this date so we could have cleared Tomcat work directory since then.
The counters have been running at least since the last restart which was 504d, 23h 10m 22s
These are really page impressions as refreshing a page does add to the counters.