NSFNET Backbone Usage Breakdown shows that between 6/94 and 12/94 that web trafic passed every thing except ftp.
NFS Traffic data shows that trafic in bytes passed ftp in 3/95 and trafic in packets passed in 4/95. see image :-
The raw traffic data also shows 4/95 as the point when www passed ftp in doth bytes and packet movements.
As Netscape navigater was released in January 1995 it is self evident as to the conclusion.