The U.S. may become the world’s biggest producer of oil and natural gas this year, but it’s still at risk from oil price shocks and supply disruptions because of its reliance on foreign supplies, according to a new analysis.

The U.S. ranks fifth out of 13 countries in oil security, trailing Japan, the United Kingdom, Canada and Germany, according to an Oil Security Index from the Securing America’s Future Energy think tank and the analytical firm Roubini Global Economics.

A report issued this week from Politico.com offer a global perspective worth considering.

It says that although the U.S. score is only modestly better than it registered early 2000, it has improved since hitting a low point in the second quarter of 2008, and gains in the past three quarters are “clear evidence that the trends of increased domestic oil production and improved efficiency are strengthening U.S. oil security, even in a historically high-price environment,” the report said.

“Despite the domestic oil boom, America’s oil security is only middle-of-the-road,” SAFE CEO Robbie Diamond said. While the boom in domestic production has helped the economy, “our nation’s oil dependence leaves the economy dangerously exposed to high and volatile oil prices,” he said.

But U.S. oil security has also been rising steadily since last year — reaching high points in both the fourth quarter of 2012 and first quarter of 2013 thanks to higher efficiency, lower per capita oil consumption, higher domestic oil production and weaker global oil prices since the unrest in Libya and elsewhere in early 2011.

The index is meant to measure a nation’s oil security by looking, in part, at its dependence, economic exposure to the global oil market and ability to respond to supply disruptions.

“Changes in the supply and cost of oil, and the demand for it, impact individual nations in different ways due to unique national strengths, weaknesses, advantages and disadvantages,” RGE Chairman Nouriel Roubini said.

The index was released as the U.S. marks the 40-year anniversary of a Saudi Arabian-led oil embargo. That disruption has prompted virtually every presidential administration since to call for a national energy plan to prevent such an occurrence from happening again.

Most experts agree that the U.S. is in a much stronger position now, with its own rising oil and natural gas production, establishment of the Strategic Petroleum Reserve and more stringent federal fuel efficiency standards.

But, Monday’s report notes, “heavy oil dependence still renders the country highly vulnerable to price fluctuations in the short-to-medium term, particularly as economic growth — and fuel demand — recovers.”

“Most measures of U.S. oil security and reliance have improved over the past decade despite the sharp increase in oil prices,” Monday’s analysis notes. U.S. “oil intensity” has decreased by a third, and the quantity of oil imports has also dropped because of higher domestic production and lower demand, it adds.

“Long-term trends in fuel efficiency and oil production growth suggest reason for optimism, but heavy oil dependence still renders the country highly vulnerable to price fluctuations in the short-to-medium term, particularly as economic growth (and fuel demand) recovers,” it said.

The other countries on the list in order are South Africa, Australia, Brazil, China, Mexico, India, Russia and Saudi Arabia.

Relatively oil-efficient countries like Japan, the U.K. and Germany sit at or near the top of the list of countries, while Canada’s rising oil exports put it in the third spot. It also scores well on security of its oil supply and total spending on net oil imports as a percentage of its gross domestic product.

Large developing nations like Brazil, China and Mexico produce a lot of oil but also have high total spending on oil as a percentage of their GDP and are showing increases in fuel consumption. Russia and Saudi Arabia have high oil exports but also high inefficiency and “overwhelming dependence” on oil exports for their domestic revenue.