Weapons sales by the United States tripled in 2011 to a record high, driven by major sales to Persian Gulf [countries], according to a new study for Congress. Overseas weapons sales by the United States totaled $66.3 billion last year, or nearly 78 percent of the global arms market, valued at $85.3 billion in 2011. Russia was a distant second, with $4.8 billion in deals. The U.S. weapons sales total was an extraordinary increase" over the $21.4 billion in deals for 2010, the study found, and was the largest single-year sales total in the history of U.S. arms exports. The previous high was in fiscal year 2009, when American weapons sales overseas totaled nearly $31 billion. Increasing tensions with Iran drove a set of Persian Gulf nations -- Saudi Arabia, the United Arab Emirates and Oman -- to spend record amounts on weapons. These states do not share a border with Iran, and their purchases focused on warplanes and complex missile defense systems. The agreements with Saudi Arabia included the purchase of 84 advanced F-15 fighters, a variety of ammunition, missiles and logistics support, and upgrades of 70 of the F-15 fighters in the current fleet ... all contributing to a total Saudi weapons deal with the United States of $33.4 billion, according to the study. The United Arab Emirates bought a Terminal High Altitude Area Defense, an advanced anti-missile shield that is valued at $3.49 billion, as well as 16 Chinook helicopters for $939 million.