I estimate 1% of the people we meet/pass in life to be alien.

I am no young Marlon Brando, but I pass some strange looking people during my adventures and the odds are we come across visitors during our life. Perhaps 1% and maybe more if you ask for such a meeting.

When you consider the population of the Earth, it makes sense. I reckon some of them seek out people who they can let in on their secret.