CREATE TABLE table_name_23 (age_as_of_1_february_2014 VARCHAR2, province_or_country_of_birth VARCHAR2)

What is the average age as of February 1, 2014 for the supercentenarians born in the United States?
SELECT age_as_of_1_february_2014 FROM table_name_23 WHERE province_or_country_of_birth = "united states"
SELECT "age_as_of_1_february_2014" FROM "table_name_23" WHERE "province_or_country_of_birth" = "united states"