plotting a vertical line

[jaolvera]

I need to plot a vertical line, that will plot using the date that is entered in a separate table. I just cant figure out how to caulate a number that will plot the line from 0 to what ever the max of x axis. 

[#2]

@jaolvera You'll need a separate series with only one data point based on the date and the max value (or max plus a little bit) on the secondary axis. Example attached.