A total of 17,479 people with dementia or suspected dementia were reported missing in Japan in 2019, the most since data began being collected in 2012, police said Thursday.

The National Police Agency data showed the figure was up 552 from 2018 and about 80 percent higher than in 2012, demonstrating the issue of dementia is becoming increasingly serious as Japan's population ages rapidly.

Of those reported missing, 245 were not found by the end of the year while 16,775, including people reported missing in 2018 or earlier, were located, according to the police data.

It showed 71.7 percent of dementia sufferers who wandered off were found on the same day their disappearance was reported to police, while 99.4 percent were located within a week. Four people were found more than two years after they were reported missing.

In the meantime, 460 missing dementia sufferers died in accidents or due to other reasons, according to the data.

With around 7 million senior citizens, or one in every five people aged 65 or older, expected to suffer from dementia in 2025, police across Japan have built a network with local governments and private companies to share information to deal with the problem of missing people.

Some municipalities assign mobile global positioning system tracking devices to dementia patients, allowing police to find them quickly if they go unaccounted for.

"It is important that an entire society tackles the issue with close cooperation between family members, municipalities and businesses," Ryota Takeda, head of the National Public Safety Commission, told a press conference Thursday.

"I will instruct police to ensure their efforts to search for and protect (dementia patients) are appropriate," he said.

In June last year, the government implemented a new program on dementia that focuses on prevention and helping patients with the illness live more comfortably.

The overall number of people who went missing last year, including those not suffering from dementia, reached 86,933, down 1,029 from 2018. Those in their 20s were the leading age group at 17,852. Of the total, 64.1 percent were male and 35.9 percent female.

Among missing people in their 70s and aged 80 or older, dementia was the largest cause of their disappearance, accounting for 64.9 percent and 77.0 percent, respectively.

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