2. The city of Elmhurst was having problems with people dumping pollution into their local river. To help with this problem, the mayor mailed pamphlets to all the citizens showing ways they could help protect the local watershed. The pamphlets were mailed each year beginning in 2005. The graph below shows how the number of stream pollution incidents changed before and after the pamphlets were mailed. What is one conclusion you can make based on the information in the graph?\
