Assertion: guinea pig | /r/ObjectUse | used in the united states
Facets:
value: for research
type: PURPOSE
value: annually
type: TEMPORAL
Source sentences:
text: Guinea pigs were popular laboratory animals until the late 20th century; about 2.5 million guinea pigs were used annually in the United States for research in the 1960s, but that total decreased to about 375,000 by the mid-1990s.