The API doc says that the SearchImpressionShare in SHOPPING_PERFORMANCE_REPORT returns a percentage as "xx.xx%", or the special value "< 10%".
However when I download the report for most of my offerIds the SearchImpressionShare has value '--'.
The number of impressions on these offersIds with '--' as SearchImpressionShare is up to 3000 per day.
Can anyone tell me what the value of '--' as a SearchImpressionShare represents?
Kind regards,
Barrie