Therefore these figures are likely to underestimate the full number of unoccupied properties as at the snapshot dates. The snapshot dates are: 31 March 2011, 17 May 2012, 1 October 2013, 1 October 2015, 5 October 2016, 1 June 2018, 31 May 2019, 1 July 2020, and 1 June 2021.