Standardised Mortality Ratio
DEATH_TOT:total * 100.0 / DEATH_TOT:expected
The actual number of deaths as a percentage of the expected number, based on national rates. This is probably the best overall measure of how healthy localities are. Rather than apply a single set of national age- and gender specific rates over more than a century, we use the Great Britain rates for the relevant year, so this is strictly a compararative measure.