During the interval in which time series overlap, the British and French negative length was growing at roughly the same rates as the US one, until 1914. That war year constitutes a great discontinuity, and from then on European growth rates are different and far lower than US ones. At the same time, the average film length increased considerably, from eighty feet in 1897 to seven hundred feet in 1910 to three thousand feet in 1920. As a result, the total released length, which is the best indicator of production, increases more rapidly than the number released, in.
