A line graph displays the annual production (in units) of two companies, X and Y. Production data is as follows:
2018: X=500, Y=300
2019: X=550, Y=400
2020: X=600, Y=350
2021: X=450, Y=500
2022: X=700, Y=400
In which year was the absolute difference in production between Company X and Company Y the highest?