In peace time, the US government used to spend very little on defense, about one percent of GDP. But that changed after World War II when the United States found itself in a global contest against Communism. Ever since, defense spending has never been less than 3.6 percent of GDP.ut 9/11, the terrorist attack on iconic US buildings in 2001, changed that, and defense spending began a substantial increase in two stages. First, it increased to 4.6 percent by 2005 for the invasion of Iraq, and then to 5.0 percent in 2008 for the the surge in Iraq.
The most noticeable difference is the sensation. A whirlpoolâs water jets come with the classic, high pressure, deep massaging jets that most people have come to associate with hydrotherapy. An air tub, on the other hand, is a more generalized, effervescent feeling.he most noticeable difference is the sensation. A whirlpoolâs water jets come with the classic, high pressure, deep massaging jets that most people have come to associate with hydrotherapy. An air tub, on the other hand, is a more generalized, effervescent feeling.
Whirlpools vs Air Tubs. Over the past few years, the industry has witnessed an explosion in the number of air system baths, with nearly every manufacturer now offering them in addition to the more familiar jetted water system baths or whirlpools that most have offered for decades.he Basics. Air systems use outside air that is heated and blown into the bath water to create an active bath. Water systems, on the other hand, use bath water that is drawn out of the bath then heated and pumped back in to create an active bath.