CREATE TABLE table_31340 ("Rank 2012" FLOAT, "Country" TEXT, "UNWTO Region" TEXT, "International tourism expenditure 2011" TEXT, "International tourism expenditure 2012" TEXT, "% change" TEXT)

How many countries spent at least $51.0 billion in international tourism in 2012?
SELECT MAX("Rank 2012") FROM table_31340 WHERE "International tourism expenditure 2011" = '$51.0 billion'
SELECT MAX("Rank 2012") FROM "table_31340" WHERE "International tourism expenditure 2011" = '$51.0 billion'