How to create a line chart that charts data from beginning of Y-Axis

I'm trying to generate a line chart from a table I've generated.

I'm having a bit of trouble in getting the line to begin so that the line touches the y-axis. As it stands the line begins halfway between the first value traced.

I've attached the file as to illustrate what I mean here.


Does anyone have any advice as to what I should do?

Many thanks.