Check webpage or reference for details of calculations. Failure to do so may result in misunderstanding results
of any analysis using the time series. Some time-series have earlier data available from the source (We usually
only supply data from 1948 onwards). The range of years covered by the different time series differs. It may
be possible to get later data from another source. Differing definitions or data sets
used in calculating some indices (e.g. PNA) will mean
that time series from different sources may not match. Being included on this page does not imply an
endorsement of the scientific validity of the time series for a particular use.