LONDON (Thomson Reuters Foundation) - Exactly 20 years ago, one lesbian couple and three gay couples tied the knot in Amsterdam's city hall - making history as the Netherlands became the first country to allow same-sex marriage, a step since followed by nearly 30 other nations.

During the two decades since the law took effect, thousands of gay and lesbian couples have wed in the Netherlands - representing 1.7% of all marriages, according to the national statistics bureau.

About 750 lesbian couples and 620 gay male couples have married on average annually over the last five years, and there are now some 20,000 married same-sex couples living in the country, official data shows.

Over the past five years, more than 400 same-sex marriages have ended in divorce on average annually - with the divorce rate for lesbian couples almost twice as high as that of gay men.

Here are some key facts about the legal recognition of same-sex couples around the world:

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- Same-sex marriage is legal in 28 countries: Argentina, Australia, Austria, Belgium, Brazil, Britain, Canada, Colombia, Costa Rica, Denmark, Ecuador, Finland, France, Germany, Iceland, Ireland, Luxembourg, Malta, Mexico, Netherlands, New Zealand, Norway, Portugal, South Africa, Spain, Sweden, Uruguay and the United States.

- A total of 34 countries recognise some form of civil partnership for same-sex couples.

- Gay marriage is hotly contested by many religious groups. Pope Francis said same-sex couples should be protected by civil union laws in a film released in October 2020, but the Vatican ruled in March that priests are not permitted to bless these unions.

- Almost a third of adults globally think people of the same sex should be allowed to marry, a survey by global LGBT+ advocacy group ILGA and research firm RIWI of almost 100,000 people in 65 countries found in 2016.

- Switzerland's parliament voted to legalise same-sex weddings in Dec. 2020, but anti-gay marriage campaigners are gathering signatures to put the issue to a national referendum this year before the law takes effect.

- In July 2020, Montenegro became the first European country outside of Western Europe and the European Union to legalise same-sex civil partnerships.

- Costa Rica marked a first in Central America by giving the go-ahead to same-sex marriages in May 2020, when a landmark constitutional court ruling came into effect.

- Northern Ireland became the last part of the United Kingdom to introduce equal marriage rights in February 2020.

- Taiwan was the first place in Asia to allow gay marriages in 2019.

- In Africa, where same-sex sexual relations are a crime in many countries and can lead to imprisonment or the death penalty, only South Africa allows same-sex marriage.