Perhaps you should try some spelling variations:
"improve national performance series." » "improve regional performance series.", "improve operational performance series.", "improve educational performance series.", "improve national performance studies.", "improve national performance size.", "improve relational performance series.", "improve maternal performance series.", "improvement national performance series."
"improving external performance reports." » "improving emotional performance reports.", "improving materials performance reports.", "improving thermal performance reports.", "improving maternal performance reports.", "improving central performance reports.", "improving federal performance reports.", "improving external performance report."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("improve national performance series.") or ("improving external performance reports."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improve national performance series.") OR ("improving external performance reports.")).
• Removing quotes may allow a broader search: (( improve national performance series. ) or ( improving external performance reports. )).
• Adding a wildcard symbol may retrieve word variants: (("improve national performance series.") or ("improving external performance reports."))*.