Type change-"totalexecutioninseconds"


We are using kibana 4.5.2 where in we want to develop a vertical report for robot utilization .
The problem is when we try to define Y-axis (sum) the field available is only levelorordinal which is number .
We would want “totalexecutioninseconds” field to be available in the drop down but it is not appearing cause it of string type

kibana 4.5.2
Elastic search : “2.3.2”,
UIPath-Version 2016.2.6274
Copyright © UiPath 2018
Orchestrator 2017.1.6435

Any input would be appreciated