How large a percentage of Saudi Arabia's export earnings come from the oil industry?

Explanation

Saudi Arabia is the world's largest oil exporter, exporting some 8,500,000 barrels a day. Russia comes second, with 7,000,000 barrels. 90% of export earnings in Saudi Arabia come from the oil industry, as well as roughly 75% of budget revenues. This means that in times of low oil prices, the state has struggled to maintain its welfare state.