The trends capability is used to determine the changes in an area over time.
For instance, to find the percentage rate of change for a given population over a given time interval, the following trends question may be asked:
"Where are the census blocks that have experienced more than a 50% population growth change between 1970 and 1990?"

trends.html
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Institute of Water Research, Michigan
State University
Last Revision: February 22, 1997