Auto Zoom for Y-Axis

[RJ]

Hello, has anyone tried to auto-zoom on a line chart? I am not seeing this option as a plugin, only seeing select-zoom options. 

We are having some issues with readability as we keep adding new years to are graphs(see photo). The website is pacinst.org/gpcd/map  Clicking on a bubble will bring up the jqplot. 

The range is needed so I can't shorten the range as a solution. 

Any ideas?