I have a set of values SLA for various category & would like to draw a static horizontal line for the SLA

eg

Sev 1 - 89, 90, 94
Sev 2 - 50, 90, 90
Sev 3 - 40, 94, 40

These are the SLA for Sev1, Sev2, Sev3 in various month, however the SLA is constant for Sev 1 as 90, sev2 as 95 & sev3 as 98 which i want to represent via horizontal line while capturing the values via bar graph.

I am unable to draw a vertical line.

Kindly help