If I recall correctly, the 30% figure applied to North America and applied to oil and natural gas combined.
Per Oil: Crude and Petroleum Products - Energy Explained, Your Guide To Understanding Energy - Energy Information Administration: U.S. Net Petroleum Imports 8,436,000 barrels/day Dependence on Net Petroleum Imports 45% And, if you click in the links in the supply column like the one that leads to http://www.eia.gov/emeu/mer/pdf/pages/sec3_7.pdf, you'll see it's higher often in better economic times. I see 60% in 2005.
