Spectrem Articles Subscription A Spectrem article subscription is required to access articles in this dashboard. Article Date: 10/01/2017 What Tax Rate Do You Want? The permanent federal income tax celebrated its 100thbirthday in the United States in 2013, a century after the ratification of the 16th Amendment to the U.S. Constitution. The federal income tax is the largest source of revenue for the U.S. government. It is also famous as one of the two unavoidables ... Log in to view full article. Sign In Forgot your password? For more information about Spectrem Articles Subscription Plan, or to purchase CLICK HERE