1step,rule,n_before,n_after,n_removed,rationale21_year_scope,keep rows with year in 2000..2022,439,439,0,Task scope; all rows already in range32_dedupe_iso3_year,"one row per (iso3, year); duplicates had identical values",439,416,23,Country identified by iso3; each country counted at most once per year43_drop_countries_missing_year_rows,drop countries without a row for every year 2000..2022,416,368,48,"Not in balanced panel (no imputation allowed): BGD, ETH, IND, NGA"54_drop_countries_with_empty_value,drop countries with an empty life_expectancy cell in any year,368,345,23,Missing country-year => not balanced (no interpolation): CHE6