Bathrooms weren't meant to be double occupancy

I have a book called the Bathroom Reader, with all kinds of short stories and trivia that you can read while in the bathroom or anyplace you're going to spent a little quality time at.  One of the statistics they mention in there is that 70% of people close the bathroom door even when they're home alone.  They seem surprised that figure is so high but I'm not.  I'm one of the 70% that closes the door even though I live alone.  I have a lot of reasons for doing so, even though I have no fear of other people walking in on me.

For one thing, I do have cats, and cat-people know how curious our little fur-babies can be.  Some cats like to be everywhere you are so if you disappear into another room, they want to follow.  I always wonder if cats know what bathrooms are for and what we're really doing in there.  I would think they would know since animals' sense of smell is better than a human's, isn't it?  So I'm not sure why a cat would want to follow me in there, unless it's to go in there after I go!  I sure don't want the cats going in there.  I have a litter box set up for them in another room for that purpose.  And I don't want them looking at me, rubbing their bodies on my legs, or jumping in my lap while I'm on the pot so I prefer to keep them out while I'm doing my business.

Another reason I close the door is to contain odors.  I might leave the door open when I'm not using the bathroom or if I just go in to wash my hands, but if I'm using the bathroom for other purposes, I prefer to keep the door closed to keep any possible sewer backups or other unwanted scents from drifting through the whole house.

Perhaps the most important reason I close the door is to stay in the habit of doing so.  If I always left the door open when I went to the bathroom at home, I might forget myself when I'm visiting someone or using a public restroom and leave the door open, enabling other people to accidentally walk in on me, leading to a mortifying incident.  Just as I store unopened mayonnaise in the refrigerator even though it could go in the pantry, so that I get used to seeing it there and don't accidentally put an open jar in the pantry, I keep the bathroom door closed so that it becomes the norm for me to see it that way and I don't leave it open in a place I shouldn't.

I have to wonder about the 30% who don't close the bathroom door at home.  What percent of them also leave the door ajar when they're away from home?  Ewwww!