Hey, that's some quality XML they're pumping out there. From their population data:
<ROWSET>
<ROW>
<Area_Code>00AA</Area_Code>
<Area_Name>City of London</Area_Name>
<Persons-1801>129000</Persons-1801>
<Persons-1811>121000</Persons-1811>
<Persons-1821>125000</Persons-1821>
<!-- ... -->
</ROW>
</ROWSET>
http://data.london.gov.uk/datastore/package/historic-census-...Embedding the year into the element name, useful that.