CREATE TABLE table_31481 ("Country" CLOB, "Number of Troops" FLOAT, "% of Total Troops" CLOB, "Troops per one million population" CLOB, "Troops per $1 billion  (  USD  )  GDP" CLOB)

Name the number of troops for troops per $1 billion being 2.45
SELECT COUNT("Number of Troops") FROM table_31481 WHERE "Troops per $1 billion ( USD ) GDP" = '2.45'
SELECT COUNT("Number of Troops") FROM "table_31481" WHERE "Troops per $1 billion ( USD ) GDP" = '2.45'