Q: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
In 2006, about 45% of the government's budget came from oil and natural gas revenues, and 31% came from taxes and fees. As of 2007[update], Iran had earned $70 billion in foreign exchange reserves mostly (80%) from crude oil exports. Iranian budget deficits have been a chronic problem, mostly due to large-scale state subsidies, that include foodstuffs and especially gasoline, totaling more than $84 billion in 2008 for the energy sector alone. In 2010, the economic reform plan was approved by parliament to cut subsidies gradually and replace them with targeted social assistance. The objective is to move towards free market prices in a 5-year period and increase productivity and social justice.
A:
By 2007, Iran's crude oil exports resulted in how much of its foreign exchange currency?