CREATE TABLE table_2202 ("Index  ( Year ) " TEXT, "Author / Editor / Source" TEXT, "Year of publication" TEXT, "Countries sampled" FLOAT, "World Ranking  ( 1 ) " TEXT, "Ranking L.A.  ( 2 ) " TEXT)

How many countries were sampled for the Prosperity Index (2008)?
SELECT MAX("Countries sampled") FROM table_2202 WHERE "Index (Year)" = 'Prosperity Index (2008)'
SELECT MAX("Countries sampled") FROM "table_2202" WHERE "Index (Year)" = 'Prosperity Index (2008)'