map 's based on ufo sighting dataset from the national ufo reporting centre and open source mapping software .
it shows 76 years of ufo sightings all over the world , with more being spotted in recent years .
surge in us sightings in the 1950s and 1960s may be explained by the testing of the u2 spy plane , cia said .
the internet and rise in drone use could explain why there are more ufo sightings than ever , experts claim .