Like-for-like sales - which strip out the effect of new store openings - fell 2.1% in the three months to 28 October.

BBC: Morrisons sales fall in 'fragile' market

So you have to find out, are 30-somethings happier than 20-somethings and, if so, can we strip that effect out of the marriage effect that may have happened at the same time?

BBC: Why it's hard to measure happiness