| S&P 500 | ZTS | | 2019 - No data 2020 - No data 2021 - 283,182 No data | 2019 - 883,764 2020 - 917,102 2021 - 934,807 6% | 2019 - 22,985 2020 - 22,378 2021 - 25,022 Fluctuating | 2019 - 3,070,960 2020 - 2,907,422 2021 - 3,288,114 Fluctuating | 2019 - No data 2020 - No data 2021 - No data No data | 2019 - 0.82 2020 - 0.46 2021 - 0.5 Fluctuating |