1.) How much of loss did the U.S. stock market experience during the period of technology bubble burst from 2000 to 2002?

2.) How much of loss did the U.S. stock market experience during the period of sub-prime mortgage crisis from 2007 to 2008?

3.) Would you still invest on stock market even if you may get hit by another market collapse with such scale in the future? Use google search to base your argument.