Bank for International Settlements (BIS)
Data categorization: year-on-year changes by per cent (ratio)
The consumer price data for the most recent periods correspond to the consumer price index published by national statistical offices. Proxy indicators, such as a consumer price index with limited coverage or a retail price index, were used to extend the series backward as far as possible.
The average length of the monthly series is close to 55 years. Some annual series go back to the middle of the 19th century - or even earlier for several countries. The BIS constructed long consumer price index series by joining the series available for consecutive periods. In undertaking this work, the BIS worked in close coordination with national authorities with the aim of providing the most accurate data possible.
The BIS’s data set for consumer prices contains long monthly and annual time series for 60 countries. The average length of the monthly series is close to 55 years. [you already said this] Some annual series go back to the mid-19th century – or even earlier for several countries. [and this] For each country, the most recent data correspond to the national consumer price index published by the statistical offices. Proxy indicators, such as a consumer price index with limited coverage1 [I am assuming this is a footnote that didn't copy-paste correctly, which means this is copied text from some unreferenced source, or plagiarized. Please do not copy-paste directly unless you quote that text and in either case, cite the source.] [also, this is a direct copy of the second sentence of the first paragraph above] or the retail price index, were used to extend the series back as far as possible.
The BIS constructed the long consumer price index by joining2 [same comment as above] the series available for consecutive periods. In doing so, it has worked closely with national authorities to provide the most accurate data possible.[this is a direct copy of the last sentence of the second paragraph] The long series are rebased and presented on a monthly and annual frequency. The publication contains both the index figures with the reference period 2010 = 100 and the year-on-year percentage changes.
The BIS long series have been used, in particular, for the calculation of the published real effective exchange rate and real residential property price [define both of these] series; they are also a useful support for macroeconomic and financial stability research. Listed below [where?] are the series used to compile the BIS long series, as well as links to websites where the most recent national data can be found. Any use of the long series should be cited as follows: “Sources: National sources; BIS long consumer prices database, www.bis.org/statistics/cp.htm.”