Read this and answer the question

The growth in women's football has seen major competitions being launched at both national and international level mirroring the male competitions. Women's football has faced many struggles. It had a "golden age" in the United Kingdom in the early 1920s when crowds reached 50,000 at some matches; this was stopped on 5 December 1921 when England's Football Association voted to ban the game from grounds used by its member clubs. The FA's ban was rescinded in December 1969 with UEFA voting to officially recognise women's football in 1971. The FIFA Women's World Cup was inaugurated in 1991 and has been held every four years since, while women's football has been an Olympic event since 1996.

Since what year has women's football been an Olympic event?
1996