Bilateral Graph URL
Bilateral graphs compare two related variables that overlap one another. In this graph, the blue line depicts the annual population change in the world in 2009, and the red line shows the world's population in 2010. On the left side of the graph, the population on 2010 is still increasing. The two lines cross at the beginning and the values change. The right side, on the other hand, shows the population in 2009 decreasing. Where the two lines overlap is where the increase in variables changes.