"We're an Army that's in uncharted territory here," says Gen. Peter Chiarelli, Army vice chief of staff, according to the report. "We have never fought for this long with an all-volunteer force that's 1% of the population."
This quote is from an article on Stars and Stripes and USA Today talking about a recent military study completed in 2010.
More quotes below the fold.
H/T to deMemedeMedia for highlighting this study in a comment.