A number of 1-day intervals for which data was collected.
The value of this object will be 7 or the maximum number of
1-day history intervals collected by the implementation unless
the measurement was (re-)started recently, in which case the
value will be the number of complete 1-day intervals for which
there are at least some data.
In certain cases it is possible that some intervals are
unavailable. In this case, this object reports the maximum
interval number for which data is available.
This object maps to the TR-159 attribute
aGroupPerf1DayValidIntervals.