Year	% of revenue
1990	0.05903187721369539
1991	4.306930693069306
1992	4.629142556549184
1993	4.9030172413793105
1994	4.90702479338843
1995	5.263157894736842
1996	5.258386219401632
1997	5.414012738853503
1998	5.3714684339030345
1999	5.6730091613812546