Yeti - 1% (People probably saw a bear or something in the dark, and thought it was apelike)
Aliens - 90% - they probably exist somewhere in the universe, but life may have such a vanishingly small probability of arising that Earth could be the only planet with intelligent life in the galaxy.
Aliens who have visited Earth: 0.000000001% - if an extra-terrestrial civilization had he technology to travel to Earth, they would probably destroy us/enslave us/colonize Earth - like Europeans going to the Americas.
Everything else - 0.1%
Aliens - 90% - they probably exist somewhere in the universe, but life may have such a vanishingly small probability of arising that Earth could be the only planet with intelligent life in the galaxy.
Aliens who have visited Earth: 0.000000001% - if an extra-terrestrial civilization had he technology to travel to Earth, they would probably destroy us/enslave us/colonize Earth - like Europeans going to the Americas.
Everything else - 0.1%
If more of us valued food and cheer and song above hoarded gold, it would be a merrier world. - J.R.R Tolkien