What is the average dealer mark up?

The dealers markup is between 40-50% depending on the company,and international distributors get 55-60% 
i was a dealer for 10 years this is the average.

First off, markup and discount are not the same number.  If a dealer is getting a 50% discount from the manufacturer from MSRP and prices at MSRP his markup is 100%.  Second to the poster above that said car dealer markups are similar, that is wrong.  Margins are so slim on new cars (other than luxury brands) that the major profit centers at new car dealers are the service centers and used car sales.  The trade-in/retail markup is quite a bit more than the new car markup.  Dealers are grossing 5 to 10% on new car sales these days.  That's why they have a person dedicated to trying to sell you snake oil wax jobs,  upholstery treatments, and overpriced extended warranties.

You can wax a car with snake oil?

" The same btw is true of most things, including cars. Which is why car dealerships are so incredibly profitable."
Not exactly.  I retired from GM and the dealer cost was typically 15-18% under MSRP.  Dealers would get a 3% bonus when a car sold, which was all the profit they got if they sold you a car at "dealer cost".  Dealers made more profit per unit on used cars, which they would buy at auction nearly every day.

Keystone (2X) is pretty standard for B&M dealers in most consumer goods, except for food and vehicles. That’s why  I ALWAYS compare online sellers (Amazon, Crutchfield, Reverb, and Sweetwater) generally before buying   Last B&M purchase was floor model top of the line Senheiser ‘phones, a Melos DAC and SONOS streamer at a Sacramento dealer Xmas sale. Mostly I buy from Amazon.