Instruct: What is the entry for Lower index MJ/ Nm 3 for the row that has an Upper index Kcal/ Nm 3 larger than 19,376, for lpg, and an Upper index MJ/ Nm 3 smaller than 86.84?
Output: SELECT AVG Lower index MJ/ Nm 3 FROM table WHERE Upper index Kcal/ Nm 3 > 19,376 AND Fuel gas = lpg AND Upper index MJ/ Nm 3 < 86.84