Achievement words need an outcome. If you do not have a number, describe the finished thing instead of borrowing a percentage.
You finished a defined piece of work.
Say what finished. Completed various duties does not tell the reader anything.
Completed the April invoice file: every payment had a matching bill.
Something measurable went down, and you can say how you know.
Do not write reduced errors by 30% unless you had a before-and-after count. Otherwise describe the change without a percentage.
Reduced end-of-day queries by writing the missing invoice number on the receipt before the customer left.
A problem is finished, not merely listened to.
If the customer is still waiting, the matter is open. Say what remains.
Resolved the double booking by moving one table and telling both guests the new time.
A later version worked better than the earlier one, in a way you can point to.
Improved team morale is hard to prove. Prefer a visible change: a checklist, a shorter queue, a cleaner handover.
Improved the handover by leaving three unfinished items on a single note instead of a verbal list.
You handed over a finished thing by a time you can name.
Delivered excellence is not a thing. Name what you handed over and when.
Delivered the signed timesheets to payroll on Friday morning.
You kept something at the standard already set.
Maintained is not the same as improved. Do not claim a rise you did not show.
Maintained the booking sheet so every cancellation had a time and a name.