Twenty

percentage of all endangered and threatened species in the U.S. that are harmed by grazing

number of plant species that provide 90 percent of the world's food supply

percent by which wind power production has grown per year since 1990

percentage of Earth's original forests that remain pristine and undisturbed

percent increase since 1945 in the agricultural harvest lost to pesticides

percentage of wood used in building a new home that could be saved by framing more efficiently

percentage of the world's endangered vertebrate species that are threatened by exotic invaders

percent by which Americans tend to overwater their lawns

percentage of the CFCs in use in 1995 that were obtained on the black market

percentage of paper produced worldwide that was discarded in the U.S. in 1994

percentage of U.S. commuters that carpooled in 1980, compared to the 8 percent that are expected to carpool in 2000

percentage of municipal solid waste that is food packaging

gallons of water can be saved by putting a trigger nozzle on a hose when washing a car

Sources:
1 -- Natural Resources Defense Council
2 -- National Wildlife Federation
3 -- Union of Concerned Scientists
4 -- Natural Resources Defense Council
5 -- Earth Communications Office
6 -- Natural Resources Defense Council
7 -- World Resources Institute
8 -- 50 Simple Things You Can Do to Save the Earth
9 -- World Resources Institute
10 -- Environmental Defense Fund
11 -- USA Today
12 -- Earth Communications Office
13 -- 50 Simple Things You Can Do to Save the Earth.