Interesting data from Andreas Marx at AV-Test.org. This chart shows the growth of unique samples (by MD5) per year.
(Data below):
Year # of unique samples (MD5)
1985 564
1986 910
1987 389
1988 1,738
1989 2,604
1990 9,044
1991 18,384
1992 36,822
1993 12,287
1994 28,613
1995 15,988
1996 36,816
1997 137,716
1998 177,615
1999 98,428
2000 176,329
2001 155,528
2002 199,049
2003 178,825
2004 142,321
2005 333,425
2006 972,606
2007 5,490,960

Have you read these related articles?
Newsletter: