Meaning of "Here take notice of a very significant truth, viz...

[Napoleon_Hill_Fan]

OK, I've come across this phrase:

"Here take notice of a very significant truth, viz:
The business depression started in 1929..."
Now, I know that viz means that is, in other words but my question is how often is this word used nowadays? This is the first time I've seen it and it appeared in Napoleon Hill's Think and Grow Rich.

[Alan]

Hi,

All I can say is that it is still in common use.

Alan
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