What is the time period used in StatisticsPlugin?

[Don Santillan]

Hello,

I would like to know how the StatisticsPlugin track statistics. For 
example on "ActiveMQ.Statistics.Broker" or 
"ActiveMQ.Statistics.Destination.<QUEUE_NAME>", it returns the 
statistics for "averageEnqueueTime", "maxEnqueueTime", and 
"minEnqueueTime". What is the period used to calculate these numbers? Or 
are they computed since the server started?

Thanks!
-don