"Forty years ago, user fees amounted to 71 percent of revenues spent on roads. Today, user fee revenue as a share of total highway-related funds is at an all-time low since the Interstate Highway System was created in 1957. A complete data set of highway revenue by source is available for download. In 2007, non-user revenues contributed $70 billion to the highway system. By comparison, this contribution totaled $26 billion in 1967 (in 2007 dollars)."You can read more at Subsidyscope.com , a project supported by the Pew Charitable Trusts.
Of course, since most bicyclists also drive, there never was a lot of validity in the assertion that we were freeriders on the roads.