Jon Taplin reproduces this jaw-dropping chart: Floyd Norris's scary graph of Durable Goods Production, adding, "We have so hollowed out our industrial plant that the only thing we are now producing is weapons of war." He goes on to quote Toynbee on Rome: "The economy of the Empire was basically a Raubwirtschaft or plunder economy based on looting existing resources rather than producing anything new. The Empire relied on booty from conquered territories… With the cessation of tribute from conquered territories, the full cost of their military machine had to be borne by the citizenry."
Update: The total numbers are better than the percentage changes: The US "remains primarily a civilian economy. Military now takes 8% of all durable goods, up from 3% in 2000."