What is the average closing price historically of DJIA?

As of 2015, the inflation-adjusted average closing price for the Dow Jones Industrial Average in the previous 100 years is $9,005.83. This figure uses month-end closings between September 1915 and August 2015.

The Dow Jones Industrial Average began in 1896 with only 12 industrial stocks, including American Tobacco, National Lead, American Sugar and the Tennessee Coal, Iron and Railroad Company, which was later acquired by U.S. Steel. It has changed the component companies 53 times since inception, expanding the field to include non-industrial corporations. General Electric, added to the index in 1907, has the longest run as a component. In March 2015, Apple Corporation replaced AT&T.