Dollar coins have never been very popular in the United States since the removal of specie coins from circulation. Despite efforts by the government to promote their use, such as the Presidential $1 Coin Program, most Americans currently use the one-dollar bill rather than dollar coins.
Width and Height. An interior passage door is any door that you use to move from one room to another, and the code requires these to be 80 inches in height. Because this corresponds to 6 feet 8 inches, door manufacturers refer to this as a 6/8 door.
The standard height for a US door is 6'-8, or 80. When framing in a rough opening, a good rule of thumb is to allow 2 extra in height and 2 extra in width. This gives you enough room to adjust the head to be level, allow for flooring, and to shim the jambs plumb. Feel free to e-mail me if you have any questions.