If you are into Top 100 chart history, the Billboard site now has every single Hot 100 chart from every single week that the chart came out. So you can watch the progression of your favorite Styx single as it made its way up and down the charts.
For example, here is the chart at Come Sail Away's peak at #8.http://www.billboard.com/charts/hot-100/1978-01-28
Other top 10s that week included: We Will Rock You/We Are the Champions, Just The Way You Are, How Deep Is Your Love, Slip Sliding Away, Stayin Alive, and the #1 song in the country, "Baby Come Back" by Player.