Classification methods

This the poverty data in the United States.  In my opinion, the best method for classification of this data  of the Quantile, Equal Interval, Natural Jenks, and Standard Deviation is the Natural Jenks.  The  poverty rates for the U.S. is not spread out evenly across the country. As you can see most states have very little poverty while other have a large impact on it.  The Natural Jenks makes natural groupings to accommodate the data and I think since there are some huge outliers within the data that it works very well.

Histogram of the Natural Jenks 

I noticed when I played around with the classes from 6 to 32 the breaks had almost evenly went throughout the data where the highest percentage of poverty was.  I did this with other classification methods and they did not break up naturally along the data, in fact, they stayed closely to where most of the data was present.