1.Northern Ireland data is only available every 3 months. Northern Ireland data is copied forward until the next data is available, which will be in the September 2019 release.
2.. From the release of September data on 17 October 2018 the indices have been re-referenced and published with January 2015=100, this allows the Northern Ireland data to be incorporated and the calculation of a UK series. Regular re-referencing of indices is methodological good practice as it avoids rounding issues that can arise from small index values. Please note that re-referencing does not impact on published inflation rates, although when using the indices to calculate inflation rates, it is important to use indices that are referenced on the same year.