Aye-yie-yie. 4.5% of GDP has disappeared from the most important part since 1Q 2006.
The biggest declines were in single-family homes, transportation equipment (this does not include personal transportation), other residences and home improvements, and computers and software. The two bubbles - dot.com (blue) and housing (orange) - can be seen plainly.
What is most disturbing about this decline is that the US already had among the lowest rate of investment in industrialized countries - only Germany was lower. (I'm still puzzled by that, though it could be a data issue.) Investment and growth go hand-in-hand. But what sector needs more investment? None that I can see, at least until obsolescence and population growth catch up to current supply - which will take 3-5 years. However, if the dollar finally falls to where it should be, construction of manufacturing structures and investment in industrial equipment will go much higher than recent levels.