Europe receives 16 percent of its natural gas from Russia through Ukraine, the Energy Department's stat shop reported on Friday.
The Energy Information Administration released analysis on the region Friday, amid the crisis, and as a number of U.S. lawmakers visited Ukraine.
And 16 percent of that total volume coming from Russia ran through Ukraine's pipeline system, according to data issued by Russia's gas exporter Gazprom, the information administration said.
In past years, up to 80 percent of Russia's natural gas exports were transported through Ukraine, but now only 50-60 percent run through the country.
The Nord Stream pipeline, which provided a direct link between Russian and Germany under the Baltic Sea, began moving natural gas in 2011, cutting the amount that flows through Ukraine.
Natural gas exports have become a contentious issue among U.S. lawmakers, as a majority of Republicans are pushing the idea to help curb Russia's influence in the region.
An attempt to attach liquefied natural gas exports to the Ukraine aid package considered by the Senate Foreign Relations Committee this week was shot down by Democrats.
The Energy Department says even if legislation were passed, allowing for the expedited approval of natural gas exports to members of the North Atlantic Treaty Organization, the U.S. and receiving countries don't have the infrastructure yet.
The export terminal closest to sending natural gas overseas won't be online till 2015 at the earliest.