Interactive timeline

• Reports/month
• Against its own era

Report counts are civilian submissions to NUFORC, not sightings. Before 1990 the ridge shows an annual average, not a monthly one — report dates from that era are reliable to the year but not the month. Reporting volume also changes with how easy reporting is; the solid line corrects for that, the faint one does not, and the corrected line starts in 2000 because earlier months have no baseline drawn from a single reporting era; the underlying NUFORC mirror runs through April 2014, and neither line counts anything reported after that month.