CREATE TABLE table_30108346_1 (number_of_troops VARCHAR(255), troops_per_$1_billion___usd___gdp VARCHAR(255))
Name the number of troops for troops per $1 billion being 2.45
    
SQL: SELECT COUNT(number_of_troops) FROM table_30108346_1 WHERE troops_per_$1_billion___usd___gdp = "2.45"