A federal tax designed to share profits from the oil and gas sector with the Australian public is barely raising a single extra dollar despite the industry's transformation from a $5 billion concern a decade ago to a $60 billion export powerhouse. With Australia poised to become the world's biggest exporter of liquefied natural gas by 2018, a Fairfax Media investigation has found revenues from the petroleum resource rent tax will remain stuck at 2003/04 levels as producers access wide-ranging tax deductions to recoup some of the $200 billion they have invested.