Adjusts the frequency of cubs input series.
.cubsTa(tsObj, conversion, frequency)A time series object.
An appropriate conversion method, i.e., "average" or "sum".
The frequency of the aggregated time series, i.e., frequency = 4 for
quarterly and frequency = 1 for annual.
If frequency == 1, then the values for the latest and the first year are
averaged over the existing months/quarters. However, for the latest year, this is only
done if the third quarter is available.