Why is the file icon usually folded from the right corner?

I'm doing a bit of iconography which got me thinking about the standard icon for a document / file shown below:

Why do the majority of these icons have the folder corner on the right hand side? Why is it seldom seen on the left and would it be detrimental to put it on the left? Is there a logical design reason for this? Or is it just a case of the first one sets the trend?

My question expands on the question here: What does an folded corner (earmarked page) represent to a user?