MANILA, Oct. 20 (Xinhua) -- The number of drug users in the Philippines has declined by more than 50 percent from 4 million in 2016 to 1.67 million in 2019, three years after President Rodrigo Duterte launched a crackdown on drug use, a survey has shown.

The Dangerous Drugs Board (DDB) of the Philippines released on Oct. 14 the survey on the patterns and trends of drug abuse results conducted from December 2019 to February 2020.

In a televised address to the nation late Monday night, Duterte cited the survey that around 1.67 million or two out of 100 Filipinos aged 10 to 69 are using illegal drugs.

Duterte warned drug users and dealers anew to stop, saying the bad habit "endangers the security" of the country.

"I grieve for the Filipinos who are victims of drugs. It pains me because (it's) a waste of life," he added.

"In the end, it will destroy the nation. If this is allowed to go on and on, and if no decisive action is taken against them, it will endanger the security of the state," Duterte said.

The DDB said the survey estimates the current user prevalence rate at 2.05 percent, significantly lower than the 2018 global estimates of 5.3 percent published in the World Drug Report 2020.

The DDB said the survey "shows a clear significant decline which can be attributed to the success of the government's anti-drug campaign and steadfast priority given by the government to create drug-free communities" under the Duterte administration.

According to the survey, cannabis or marijuana is the most commonly abused dangerous drug, followed by methamphetamine hydrochloride.

The survey finds that, for lifetime users, the average age when most of them started trying drugs is 22 years old. "Of the current users, on the other hand, most belong to the age group of 18 to 59 years old," the DDB said.

About 65.8 percent of the respondents are aware of the government's campaign against illicit drugs. Of those who are aware, 81.6 percent approves of the campaign, the DDB said.

Respondents of the survey are Filipinos aged 10 to 69 randomly selected from 9,341 households in all the 17 regions of the country.