Perhaps you should try some spelling variations:
"helped decrease" » "helped decreased" (Expand Search), "helped increase" (Expand Search)
"tier decrease" » "tier decreased" (Expand Search), "tier increase" (Expand Search), "tie decrease" (Expand Search)
"steer decrease" » "steer decreased" (Expand Search), "steer increase" (Expand Search), "steel decrease" (Expand Search)
"mean decrease" » "mean decreased" (Expand Search), "mean increase" (Expand Search)

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("helped decrease") OR ((("tier decrease") OR ("steer decrease"))))) OR ("mean decrease"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"helped decrease\") OR (((\"tier decrease\") OR (\"steer decrease\"))))) OR (\"mean decrease\"))*".
• Removing quotes may allow a broader search: (((( helped decrease ) OR ((( tier decrease ) OR ( steer decrease ))))) OR ( mean decrease ))*.