It costs about 50 cents per mail piece in the US. It’s probably the cheapest marketing approach for a lot of companies.

Examples were voter registration cards, credit card replacements or a mailed check.

I live in the US. I used “Government” as a broad category to include Mail from the federal government in addition to the state and the city. The city sends junk Mail more often than not.

We are a 2 person household between me and my wife. I logged all of our received mail from our mailbox every day in a sheet then converted the data into a json node so I can use http://www.sankey-diagram-generator.acquireprocure.com/
to generate this diagram. I categorized each mail piece into broader
categories to be able to make this Sankey chart readable. I categorized
any unsolicited mail into Junk Mail. Only of 5 out of 425 mail pieces was
mail that could not have been sent in an email.