Options Outstanding Number Weighted-Average Exercise Price (USD) Balances as of December 31, 2017 21,647,350 61.13 Granted 2,039,974 311.66 Exercised -3,208,046 38.63 Balances as of December 31, 2018 20,479,278 89.61 Granted 2,588,380 320.66 Exercised -2,208,332 32.88 Balances as of December 31, 2019 20,859,326 124.28 Granted 1,909,476 432.34 Exercised -4,091,992 58.30 Balances as of December 31, 2020 18,676,810 170.23