Seoul, Oct 27 (IANS): More than three quarters of North Korea's missile tests conducted since 1984 were deemed to be successful, new data revealed on Thursday,.

The US-based James Martin Center for Nonproliferation Studies produced the data on the North's testing of missiles capable of delivering a payload of at least 500 kg at a distance of at least 300 km, reports Yonhap News Agency.

Of the 204 missiles tested by the North since 1984, 156 were classified as successes, 32 as failures and the rest as "unknown", according to the institute's data posted on the Nuclear Threat Initiative's website.

The figure translates to a success rate of 76 per cent over the period.

The overall success rate stood in stark contrast with the 1984-1992 period, during which only five out of the total 10 missile launches were rated as successes.

The database also analysed 44 North Korean missile tests conducted this year.

As of October 14, the tests included 27 successes and four failures, which led to a success rate of 61 per cent.

Pyongyang has recently ratcheted up regional tensions with a range of missile tests, including those involving an intermediate-range ballistic missile and a long-range cruise missile earlier this month.