Y axis break to show two separate ranges on a line graph???

Office 365 w Excel 2016

Have a line graph that has numerous points in the "20" range and numerous points in the "100" range.  No points between 30 and 85 so I have a big white space and "busy" areas high -100 and low - 20 that I cannot expand since I have so much white space.  The Y axis is not from the data, but a range made up under Format Axis.  Can I do a break the way I have it or do I need to create a data column with the numbers I need somehow to get rid of the "white space gap"?  Thanks