Just how well have U.S. defense firms done in the past few years? To put it in context, in the past 24 months, the U.S. stock market has been on a nearly unprecedented tear. Since April of 2013, the Standard & Poor’s 500 index has soared, increasing in value by more than 30 percent.Compared to a broad index of the defense industry, the S&P 500 looks like a bad investment. Since April of 2013, the Dow Jones U.S. Aerospace and Defense Total Stock Market Index has grown at double the rate of the S&P, increasing in value by 60 percent.Making the performance of defense firms even more remarkable is the fact that their share prices continued to surge even as the U.S. Budget sequester took hold, slashing the Pentagon’s budget by tens of billions of dollars. In 2014, for example, U.S. military spending fell by 6.5 percent, according to the Stockholm International Peace Research Institute.The reason for defense firms’ continued success, according to a report issued this month by SIPRI, is that the U.S. has been the outlier in that respect recently. “Excluding the USA, total military expenditure for the ‘rest of the world’ has increased continuously since 1998 and was up by 3.1 per cent in 2014,” the report concluded.