Two reconstructed HCD country-years. Both-sex period life expectancy is built here from the sixteen cause rates and carried apart by cause.
Each front's running total as it advances, in years. That total is the gain after replacing the reference schedule's all-cause mortality with the comparison's, band by band, and rebuilding the table. Both end on the whole difference. Bars and cells fill only after both fronts have passed an age.
Mortality is taken from the first schedule and replaced, band by band, with the second's. Life expectancy is rebuilt here from the sixteen cause rates, in years, not from the HMD table.
Pick the same year in two countries for a geographic differential, or the same country in two years for a temporal one. Each country offers only the years the reconstructed series holds for it.