Just bought a new Yaris and am looking to tint my windows myself, so I was looking up information regarding it and came across your question while Googling.
Here are the legal tint limits for each state, according to Wikipedia:
Alabama 32% - Louisiana 40% - Ohio 50%
Alaska 70% - Maine 50% - Oklahoma 25%
Arizona 33% - Maryland 35% - Oregon 35%
Arkansas 25% - Massachusetts 35% - Pennsylvania 70%
California 70% - Michigan 70% - Rhode Island 70%
Colorado 27% - Minnesota 50% - South Carolina 27%
Connecticut 35% - Mississippi 28% - South Dakota 35%
Delaware 70% - Missouri 35% - Tennessee 35%
Florida 28% - Montana 35% - Texas 35%
Georgia 32% - Nebraska 35% - Utah 43%
Hawaii 35% - Nevada 28% - Vermont 70%
Idaho 35% - New Hampshire 70% - Virginia 43%
Illinois 70% - New Jersey 70% - Washington 35%
Indiana 30% - New Mexico 20% - West Virginia 35%
Iowa 70% - New York 70% - Wisconsin 50%
Kansas 35% - North Carolina 32% - Wyoming 28%
Kentucky 35% - North Dakota 70%
The lower the percentage, the darker the tint.
2013 MERCEDES BENZ SL-CLASS