Link: https://www.reddit.com/r/OnePiece/comments/10vu88k/chapters_per_year/
1997- 21 chapters (1 - 21)1998 - 48 chapters (22 - 69)
1999 - 48 chapters (70 - 117)
2000 - 48 chapters (118 - 165)
2001 - 48 chapters (166 - 213)
2002 - 46 chapters (214 - 259)
2003 - 45 chapters (260 - 304)
2004 - 45 chapters (305 - 349)
2005 - 45 chapters (350 - 394)
2006 - 45 chapters (395 - 439)
2007 - 44 chapters (440 - 483)
2008 - 43 chapters (484 - 526)
2009 - 42 chapters (527 - 568)
2010 - 40 chapters (569 - 608)
2011 - 42 chapters (609 - 650)
2012 - 43 chapters (651 - 693)
2013 - 39 chapters (694 - 732)
2014 - 39 chapters (733 - 771)
2015 - 39 chapters (772 - 810)
2016 -40 chapters (811-850)
2017 - 39 chapters (851-889)
2018 -39 chapters (890- 928 )
2019 - 38 chapters (929-966)
2020- 33 chapters (967-999)
2021- 36 chapters (1000-1035)
2022- 35 chapters (1036- 1070)
2023- 32 chapters (1071- 1102)
2024- ???
comment from @duck_master
A quick calculation: One Piece has been around for 27 years. In that time, in only 5 years has the number of chapters strictly increased from the previous year (namely 1998, 2011, 2012, 2016, and 2021).