* Apollo 14: Returned 94.4 pounds (42.8 kilograms) of lunar samples.

* Apollo 15: Returned 170.5 pounds (77.4 kilograms) of lunar samples.

To find the difference:

170.5 pounds (Apollo 15) - 94.4 pounds (Apollo 14) = 76.1 pounds

Therefore, Apollo 15 returned 76.1 pounds more lunar material than Apollo 14.