Assertion: gull's population | /r/CapableOf | decline of about 40%
Facets:
value: in only three generations
type: TEMPORAL
Source sentences:
text: Since 1970s, its it believed that the global population of black-legged kittiwake has declined of about 40% in only three generations (one generation is in average 12.9 years), putting the species in a dangerous place for the future.