Table: uruguay_intl_rankings
Columns: index_year
author_editor_source
year_of_publication
countries_sampled
world_ranking_1
ranking_l_a_2

Question: How many items were under ranking l.a.(2) when the world ranking was 21st?
SQL: SELECT COUNT("ranking_l_a_2") FROM uruguay_intl_rankings WHERE "world_ranking_1" = '21st'

Question: What was the author/editor/source when the l.a. ranking was 1st?
SQL: SELECT "author_editor_source" FROM uruguay_intl_rankings WHERE "ranking_l_a_2" = '1st'

Question: How many years were listed under index when there were 157 countries sampled?
SQL: SELECT COUNT("index_year") FROM uruguay_intl_rankings WHERE "countries_sampled" = 157

Question: What was the publication year ranking l.a. is 1st?
SQL: SELECT "year_of_publication" FROM uruguay_intl_rankings WHERE "ranking_l_a_2" = '1st'

Question: How many years were recorded when world ranking was 21st?
SQL: SELECT COUNT("index_year") FROM uruguay_intl_rankings WHERE "world_ranking_1" = '21st'