Question: What is the lowest 2013 population estimate of south africa, which has a percentage greater than 19.8 and a 2011 population greater than 51770561?
SQL: SELECT MIN("Population Estimate (2013)") FROM "2-1860337-1" WHERE "Percentage" > 19.8 AND "Province" = 'south africa' AND "Population (2011)" > 51770561.0;

Question: What is the rank of the Gauteng province?
SQL: SELECT "Rank" FROM "2-1860337-1" WHERE "Province" = 'Gauteng';

Question: What is the lowest 2013 population estimate of the province with a 23.7 percentage?
SQL: SELECT MIN("Population Estimate (2013)") FROM "2-1860337-1" WHERE "Percentage" = 23.7;