Illinois had the 6th highest self-response rate in the nation and River Forest was among the top 100 Illinois cities. Some neighbors:
Chicago 60.9
Riverside 83.1
North Riverside 78.7
LaGrange 78.0
Elmwood Park 69.1
Maywood 63.7
River Forest 83.3
Oak Park 74.2
Forest Park 71.7
Total results of the census by state can be accessed here.