100% Stacked Column and line chart

Hi,

I know there is already a thread here with the same title which I've tried to follow but can make it work. I think because I have multiple values to display. 

What I'm trying to create is a 100% stacked column and line chart. There are four time bands I would like to display as a 100% stacked column chart, with the percentage resolved within SLA as a line on top. I've created the below column to separate the time bands but I can't work out how to create a % measure from it as was suggested in the previous post. 100% STACKED column and line chart 

Resolve Time Bands = IF(PowerBI_SERVICE_DB[Resolve_time_mins]<240,"0-4hrs",

IF(AND(PowerBI_SERVICE_DB[Resolve_time_mins]>=240,PowerBI_SERVICE_DB[Resolve_time_mins]<480),"4-8hrs",

IF(AND(PowerBI_SERVICE_DB[Resolve_time_mins]>=480,PowerBI_SERVICE_DB[Resolve_time_mins]<960),"8-16hrs",

IF(PowerBI_SERVICE_DB[Resolve_time_mins]>960,">16hrs"))))

This is the result when put on a stacked column chart:

 

I need it to return 100% stacked so I can put a line over the top for the SLA measure, as if I was using a 100% stacked column chart

Thanks in advance!

 

Kind Regards,