Why is the year 2001 missing from GNU make (manual) copyright?

[Blaž Merela]

Dear all,

perhaps an odd/silly question, but the GNU make manual has year 2001 missing from its (C). 

Copyright © 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.

The maintainers guide says, that 

> To update the list of year numbers, add each year in which you have made nontrivial changes to the package.

Were there really no "nontrival changes" being made in the year 2001? Or did you just forget to put in 2001 as well? 

It just seems off that in all other 20+ years of GNU make there was something being worked on?

Kind regards and thank you for any answer,

Blaise