Victor airways in USA

[dfs346]

The FAA Historical Chronology 1926-1996 states "Jun 1, 1952: Forty-five thousand miles of very-high-frequency (omnirange) airways, referred to as "Victor" airways, were put in operation. Like the then existing 70,000 miles of Federally maintained low-frequency airways, the "Victor" routes were 10 statute miles in width."

So Victor airways originally had a width of 10 sm (8.68 nm). Today, the standard width is 8nm.

Does anyone know when the change in width occurred?

[dfs346]

Further to a FOIA request to the FAA, I  received the answer, as follows:
 "The final rule was published on July 7, 1964.  Section 71.5 established the width of 4 miles either side of centerline.  Section 71.19 adopts nautical miles as the measurement.  Both sections are on page 8472 of the rule"