And most of those dollars still come from companies that sell boats, fishing equipment and other marine-related products.

FORBES: Reeling In Sponsors

Russia has provided Teheran with nuclear-related technologies, missile components and other advanced equipment.

CENTERFORSECURITYPOLICY: Russia's Oil Grab

The other 20% are mainly due to faulty equipment and unsafe, weather-related flying conditions.

BBC: How human error can cause a plane crash