Defense contracting is a growing, multi-billion dollar industry. US Army Ordnance Dept. poster (Minnesota Historical Society)

President Eisenhower warned of the rise of the military industrial complex in his 1961 farewell address.

It's impossible to know for sure if he was thinking of companies like these, selling about $235 billion in arms every year, but it's possible.

Making weapons has become a U.S. specialty, with 47 American companies filling the top 100 grossing slots in the world.

The following numbers are put together by SIPRI based on numbers from 2010, rank in terms of sales, and offer an unbiased view of how big a business war has become.