Formula Query Execution took too long - List All table

We have a table with a bit over 9,000 records and 184 fields. Table size is 4.8 MB, with 150 MB of attached files, and the statistics screen says it is less than 1% full.

Recently, we have been getting the error "Formula Query Execution took too long" when attempting to load the List All report for this table. 

The table lists vehicle assignments, and we sometimes need to look back at assignment histories, so I would prefer not to delete any records.

Why would we be getting this error, and is there anything I can do to prevent it?

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Amy Christensen
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