Residential dwelling ages, grouped into approximately 10-year age bands from pre-1900 to 2015. Counts of the numbers of properties in each LSOA11CD (around 1000 properties), in each group. The original source also splits out by council tax bands.
The data is generally rounded (at source) to the nearest 10. However, where there are more than 0 but less than 5 properties, then the value "1" is assigned. Because of the rounding, then the total population may not be equal to the sum of the constituent populations, for some areas.
The "Mode 1" columns relate to the modal age grouping, i.e. the grouping with the most number of properties in it. "Mode 2" is the runner-up age grouping, i.e. the grouping with the second-most number of properties in it. It may be that there are two or more groupings with the same maximum population, in which case Mode 1 is assigned to the most recent one, Mode 2 to the second-most recent etc.