What is the change in population since 1993 in the region where the % of country's population was 4.2?
create table table_2637317_1 (change_in_population_since_1993 varchar, _percentage_of_countrys_population varchar, PRIMARY KEY (change_in_population_since_1993))
select count(change_in_population_since_1993) from table_2637317_1 where _percentage_of_countrys_population = "4.2"