These two websites show the percentages of Africa and the world that are deserts.
http://wiki.answers.com/Q/What_percentage_of_Africa_is_desert
What do you mean by America? the U.S.? North America and South America?
What are the desirtification percentages in Africa, America, and the world?
4 answers
By america i mean just North America
I couldn't find the exact statistics for North America, but as you can see from this map, deserts cover 5% or less of North America.
http://ag.arizona.edu/~lmilich/desert.html
http://ag.arizona.edu/~lmilich/desert.html
Here's the other site.
http://www.galeschools.com/environment/biomes/desert/index.htm
http://www.galeschools.com/environment/biomes/desert/index.htm