You might want to adjust the figure to account for clothing/minimal construction work for shelter - both are definitely fundamental in most parts of the US. One might also wish to add in a minimally functional healthcare system to ensure a reasonably high average life expectancy.

Nevertheless, the point is still extremely valid; I would estimate around 95%.

Update: As in general it is easy to draw overly pessimistic conclusions from this (I have been affected by this myself), it may be of use to point out that positive answers do exist for this issue. One of my personal favorites is the powerful, short book "Man's Search for Meaning" by Viktor Frankl.