Engelworks
Rookie
Federer
1998: 40%
1999: 50%
2000: 38%
2001: 23%
2002: 19%
2003: 11%
2004: 8%
2005: 1%
2006: 1%
2007: 5%
2008: 11%
2009: 10%
2010: 9%
2011: 9%
2012: 8%
2013: 18%
2014: 7%
2015: 7%
2016: 14%
2017: 7%
2018: 10%
Nadal
2002: 50%
2003: 40%
2004: 34%
2005: 8%
2006: 13%
2007: 8%
2008: 8%
2009: 10%
2010: 5%
2011: 8%
2012: 8%
2013: 4%
2014: 14%
2015: 19%
2016: 19%
2017: 8%
2018: 6%
Djokovic
2004: 60%
2005: 45%
2006: 24%
2007: 13%
2008: 10%
2009: 10%
2010: 18%
2011: 7%
2012: 6%
2013: 6%
2014: 4%
2015: 2%
2016: 8%
2017: 15%
2018: 12%
Example of calculation: In 2002, Federer played 80 ATP matches, and 15 of those matches (15/80*100 = 19%) were losses against someone who was not the eventual tournament champion.