Assertion: challenge | /r/CapableOf | taper off to its previous level
Facets:
value: by 2014.[non-primary source
type: TEMPORAL
Source sentences:
text: The challenge has been described online since 2001, and increased in popularity in 2007, peaking abruptly in January 2012 and falling off almost as sharply through the first half of that year, then tapering off almost to its previous level by 2014.[non-primary source needed]