Around $6.2 million-worth of cryptocurrency was hacked from exchange accounts and wallet services in Japan last year, new data reveals.

According to Japanese news source Nikkei, the country’s National Police Agency (NPA) released its first annual report of statistics tracking thefts from cryptocurrency accounts on Thursday.

The data shows that at least 149 cases of hacking emerged last year, with 16 cryptocurrency exchanges affected, as well as three wallet operators, through which around 662 million Japanese yen was illegally remitted. Bitcoin was as the biggest crypto target, with 85 BTC stolen, the report says.

While the agency did not disclose the name of the services affected, it noted that the recent $530 million hack of the Coincheck exchange is not included in its 2017 statistics.

Out of all the thefts, 122 cases – accounting for over 80 percent of the total – did not incorporate extra levels of security such as two-factor authentication, the report indicates.

Furthermore, a growth in the number cases was seen to coincide with the increasing price of bitcoin and the wider cryptocurrency market. For example, data shows that unauthorized remittances increased from 7 cases in April to 19 and 41 in May and June, respectively.

The data release comes as an effort by the agency to investigate thefts of assets from cryptocurrency investors in Japan following the notorious collapse of the Mt. Gox exchange in 2014 and the government’s extensive actions in force exchanges to protect cryptocurrency investors since.

Japan police car image via Shutterstock