So this population U.S. census data just came out a few days ago -
State Totals: Vintage 2013 - U.S Census Bureau
Here is the fastest growing states from 2010 to 2013 and the population growth rate:
1. North Dakota 7.6%
2. District of Columbia 7.4%
3. Texas 5.2%
4. Utah 5.0%
5. Colorado 4.8%
6. Florida 4.0%
7. South Dakota 3.8%
8. Washington 3.7%
9. Arizona 3.7%
10. Alaska 3.5%
Here is the slowest growing states from 2010 to 2013 and the population growth rate:
1. Rhode Island -0.1%
2. Maine 0.0%
3. West Virginia 0.1%
4. Michigan 0.1%
5. Vermont 0.1%
6. Ohio 0.3%
7. Illinois 0.4%
8. New Hampshire 0.5%
9. Pennsylvania 0.6%
10. Connecticut 0.6%