CREATE TABLE table_2637317_1 (change_in_population_since_1993 VARCHAR(255), _percentage_of_countrys_population VARCHAR(255))
What is the change in population since 1993 in the region where the % of country's population was 4.2? 
    
SQL: SELECT COUNT(change_in_population_since_1993) FROM table_2637317_1 WHERE _percentage_of_countrys_population = "4.2"