I swear there's a ghost in my house

[KruzeS]

ArtofAngels said:
And who's to say every dead person equals one more ghost?? And besides, there are more people alive today then the total amount of deaths ever in the human race.

http://www.madsci.org/posts/archives/2000-05/957452021.Ev.r.html 

And that's a low estimate.