Range graded proportional circle map

http://www.personal.psu.edu/users/a/g/agc135/486/Lesson8/Lesson8.html

Range graded proportional circle maps are maps that use circles to show data in a certain area. The more variable there is in an area the larger the circle. The map I chose shows the burglary rate from 1998-2003. The areas with higher burglary rates have larger circles.