In North America, humans now spend approximately 90 percent of their time indoors and a further 5 percent in cars, leaving only 5 percent of the time when they are outdoors (Leech et al, 1996)I'm not sure if this is waking time or based on 24-hour day. But still, we need to be outside more, trees and earth and sky is so much more inspiring than four walls and furniture!!! enjoy it while you can before it gets too cold! (if you're reading from somewhere in N. America that is). This stat is pretty accurate for me in the winter, but this summer I often spent 4-5 hours outside everyday.
I got this stat from an interesting report on Urban Ecosystems and Human Health that i'm reading for my Environment and Resource Studies course called "Building Sustainable Communities"