SYDNEY (Reuters) - Australia on Thursday marked the 20th anniversary of a mass shooting which led to strict gun controls that have in turn led to a huge decline in gun murders, undermining claims in the United States that such curbs are not the answer.

The chances of being murdered by a gun in Australia plunged to 0.15 per 100,000 people in 2014 from 0.54 per 100,000 people in 1996, a decline of 72 percent, a Reuters analysis of Australian Bureau of Statistics figures showed.

In 1996, Australia had 311 murders, of which 98 were with guns. In 2014, with the population up from about 18 million to 23 million, Australia had 238 murders, of which 35 were with guns.

It was the April 28, 1996, shooting deaths by a lone gunman of 35 people in and around a cafe at a historic former prison colony in Tasmania that prompted the government to buy back or confiscate a million firearms and make it harder to buy new ones.

The country has had no mass shootings since.

The figures directly contradict assertions of most leading U.S. presidential candidates who have either questioned the need to toughen gun laws or directly denounced Australia’s laws as dangerous.

In a January 2015 tweet, Republican front runner Donald Trump wrote “Fact – the tighter the gun laws, the more violence. The criminals will always have guns”. A year later, Republican hopeful Ted Cruz blamed Australia’s gun laws on a rise in sexual assault.

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Democrat front runner Hillary Clinton has meanwhile ruled out an Australian-style gun buyback, while Democrat hopeful Bernie Sanders has rejected the need for tougher gun controls despite a gun murder rate of 3.4 per 100,000.

The U.S. National Rifle Association has attacked the Australian laws as “not the definition of common-sense”.

Philip Alpers, an associate professor of University of Sydney’s School of Public Health, who studies gun ownership and violence, said Australia’s laws had had “demonstrable success”.

“We have the most comprehensive suite of gun laws (in the world) and it would be a great shame to start whittling those down,” he said.

Australian Prime Minister Malcolm Turnbull marked the anniversary by saying U.S. gun violence showed why Australia would keep its laws intact.

The rate of U.S. gun deaths shows “what happens when you have very little if any restrictions on the purchase of weapons like that”, he told the Australian Broadcasting Corp.