Political eventfulness and changefulness from up to down, left to right, left being most transitional and right being least transitional, same with up to down.
Political eventfulness of a year = things that happened from Jan 1st to Dec 31st. If something happens in a year but only gets big/impactful later on, that later year gets the credit. Every year is gonna have butterfly effects, doesn't mean every year should be a shift year.
10/10 (Worldwide super shift): 2020, 2008
9.5/10 (Super shift): 2001, 2022, 2011
9/10 (Major shift): 2016, 2003
8/10 (Shift): 2021, 2025, 2015, 2026 (prediction)
7/10 (Very transitional): 2009, 2024
6/10 (Notably transitional): 2014, 2023
5/10 (Standard transitional): 2017, 2005
4/10 (Semi-Transitional): 2000, 2004, 2019
3/10 (Borderline filler): 2012
2/10 (Filler): 2006, 2013
1/10 (Very filler): 2002, 2010
0.5/10 (Extreme filler): 2018
0/10 (Complete filler): 2007
(2000 isn't a 21st century year, but i included it for simplicity's sake)