CREATE TABLE table_64433 ("Fuel gas" TEXT, "Upper index Kcal/ Nm 3" FLOAT, "Lower index Kcal/ Nm 3" FLOAT, "Upper index MJ/ Nm 3" FLOAT, "Lower index MJ/ Nm 3" FLOAT)

What is the Upper index Kcal/ Nm 3 of iso-butane, and a Lower index MJ/ Nm 3 smaller than 84.71?
SELECT COUNT("Upper index Kcal/ Nm 3") FROM table_64433 WHERE "Fuel gas" = 'iso-butane' AND "Lower index MJ/ Nm 3" < '84.71'
SELECT COUNT("Upper index Kcal/ Nm 3") FROM "table_64433" WHERE "Fuel gas" = 'iso-butane' AND "Lower index MJ/ Nm 3" < '84.71'