Kibana version : 5.4.0

Hello .

I have a goal to achieve but struggling with kibana interface so I would like to get some help with this.

## My Goal

I will need to achieve below 2 steps

- Calculate the
*cumulative sum*of field*spamscore*using the histogram bucket - Using the
*cumulative sum*I will need to calculate the ratio of against the*total hits*of search period.

For step2 , I will need to divide each histogram bucket by *73* (e.g 3 / 73 , 5/73,etc )

Currently, I have achieved step1 as below.

However, I am struggling with Step2. After reading the document , I assume that I will need to write script but not sure **where to write it** and **how to access the cumulative sum series as doc field** .

May I ask how can I achieve my goal?