A blogger on data analysis website Quantbait, Levi Pearson, created a map using data from the National UFO Reporting Center and map making software CartoDB.
The first reported UFO sightings were seen over the skies of California and Nebraska in the US, the UK and France, over Europe and locations in Japan and Australia in 1933.
The number of sightings increased dramatically between the 1940’s and the 1960’s, but that may have been down to World War 2 and the Cold War.
Then there was the 90’s when we had the X-Files with Mulder and Scully which probably contributed to some sightings during those years.
Anyway check out the map