pre_text: Disaggregation of revenue The following table provides information about disaggregated revenue by primary geographical markets: The Company derived over 90%, and approximately 88% and 84% of subscription revenues from RingCentral Office product for the years ended December 31, 2019, 2018 and 2017, respectively
table: Year ended December 31,
table: 2019 2018 2017
table: Primary geographical markets
table: North America 93% 95% 96%
table: Others 7% 5% 4%
table: Total revenues 100% 100% 100%
question: Analyse this data from a financial earnings document. What is the change in percentage of total revenue earned in North America between 2017 and 2018?