This nation has given australia its greatest economic boost through its purchase of australia's natural gas. united states china japan new zealand

Australia is known to have large resources of coal, uranium and natural gas, where oil, gas and energy industries are the major contributors in their economy.  Australia's petroleum industry has contributed $6.2 billion per annum to their GDP.

In terms of its petroleum industry, the Liquid Natural Gas (LNG) is the fastest growing energy sector that promises continued growth. This is because Australia is the world's fifth largest exporter of LNG, where Japan is considered to be the primary importer. Likewise, Japan is also Australia's top export market for coal.

C.about 10% i think