The number of previous near end intervals for
which data was collected. The value will be
96 unless the interface was brought online within
the last 24 hours, in which case the value will be
the number of complete 15 minute near end
intervals since the interface has been online. In
the case where the agent is a proxy, it is
possible that some intervals are unavailable. In
this case, this interval is the maximum interval
number for which data is available.