Film production in the UK has experienced a number of booms and recessions. Although many factors can be used to measure the success of the industry, the number of British films produced each year gives an overview of its development: the industry experienced a boom as it first developed in the 1910s, but during the 1920s experienced a recession caused by US competition and commercial practices. The Cinematograph Films Act 1927 introduced protective measures, leading to recovery and an all-time production high of 192 films in 1936. Production then declined for a number of years. Film production recovered after the war, with a long period of relative stability and growing American investment. But another recession hit the industry in the mid-1970s, reaching an all-time low of 24 films in 1981. Low production continued throughout the 1980s, but it increased again in the 1990s with renewed private and public investment. Although production levels give an overview, the history of British cinema is complex, with various cultural movements developing independently. Some of the most successful films were made during 'recessions', such as Chariots of Fire (1981).