Assertion: pandemic influenza | /r/HasProperty | infrequent
Facets:
value: in 1968
type: TEMPORAL
value: in 1957
type: TEMPORAL
value: in 1918
type: TEMPORAL
Source sentences:
text: It appears to be infrequent and unpredictable, with three pandemics having occurred in the past 100 years — in 1918, 1957 and 1968.