The document outlines the progression of taxis through time from 1769 to present day. It notes the years that taxis first appeared powered by steam from 1769 to 1801. It then lists decades from 1840 to 1910 where the taxi industry continued to evolve. Finally it mentions key years from 1920 to 2000 where the taxi industry modernized and became established, and concludes with taxis in 2009. The document uses dates to chronologically chart the development of taxis over approximately 240 years.