2020-S should not be that difficult to find, it has the second highest number of sales. 
Here are the sales numbers for the proof sets through 11/9/2015:
Here are the sales numbers for the proof sets through 11/9/2015:
19GA 2019 AI $1 PROOF SET 149,885 11/9/2025 20GA 2020 AI $1 PROOF SET 108,400 11/9/2025 21GA 2021 AI $1 PROOF SET 91,273 11/9/2025 22GA 2022 AI $1 PROOF SET 85,200 11/9/2025 23GA 2023 AI $1 PROOF SET 61,841 11/9/2025 24GA 2024 AI $1 PROOF SET 66,035 11/9/2025 25GA 2025 AI $1 PROOF SET 52,364 11/9/2025





















