CREATE TABLE table_24620684_2 (operating_mode VARCHAR, epa_rated_combined_fuel_economy VARCHAR)

When 87 mpg-e (39kw-hrs/100mi) is the epa rated combined fuel economy how many operating modes are there?
SELECT COUNT(operating_mode) FROM table_24620684_2 WHERE epa_rated_combined_fuel_economy = "87 mpg-e (39kW-hrs/100mi)"
SELECT COUNT("operating_mode") FROM "table_24620684_2" WHERE "87 mpg-e (39kW-hrs/100mi)" = "epa_rated_combined_fuel_economy"