Conditionally remove a field in Splunk

I have a table generated by chart that lists the results of a compliance scan

These results are typically Pass, Fail, and Error – but sometimes there is "Unknown" as a response

I want to show the percentage of each (Pass, Fail, Error, Unknown), so I do the following:

| fillnull value=0 Pass Fail Error Unknown
| eval _total=Pass+Fail+Error+Unknown
<calculate percentages for each field>
<append "%" to each value (Pass, Fail, Error, Unknown)>

What I want to do is eliminate a "totally" empty column, and only display it if it actually exists somewhere in the source data (not merely because of the fillnull command)

Is this possible?

I was thinking something like this, but cannot figure out the second step:

| eventstats max(Unknown) as _unk
| <if _unk is 0, drop the field>

from User warren – Stack Overflow https://stackoverflow.com/questions/74541096/conditionally-remove-a-field-in-splunk
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