We operate a global marketplace, where hosts offer guests stays and experiences on our platform. During 2019, we had 54 million active bookers and 247 million guest arrivals. As of September 30, 2020, our more than 4 million hosts had 7.4 million available listings of homes and experiences, of which 5.6 million were active listings. Our listings include private rooms, entire homes, luxury villas, treehouses, igloos, and experiences, in approximately 100,000 cities across more than 220 countries and regions. In 2019, 63% of our revenue was generated from listings outside of the US. We believe that we have the largest collection of unique listings available for guests. Approximately 76% of active listings had been booked in the twelve months ended September 30, 2020 and 90% had been booked in the 24-month period ended September 30, 2020. As hosts become more successful on our platform and as guests return over time, we benefit from the recurring activity of our community. For example, in 2019, 84% of our revenue resulted from stays with existing hosts who had completed at least one guest check-in on or before December 31, 2018, up from 82% in 2018 and 77% in 2017. In addition, 69% of our revenue in 2019 was generated from stays in that year by repeat guests, up from 66% in 2018 and 62% in 2017.