CREATE TABLE table_name_99 (population VARCHAR, gdp_per_capita__us$_ VARCHAR)

What is the population of the nation that has a GDP per capita (US$) of 11,929?
SELECT population FROM table_name_99 WHERE gdp_per_capita__us$_ = "11,929"
SELECT "population" FROM "table_name_99" WHERE "11,929" = "gdp_per_capita__us$_"