Thailand's skill in English has fallen for the third year in a row, according to the annual English Proficiency Index conducted by EF Education First.

The report showed Thailand dropped to 74th out of 100 countries with a score of 47.62, which is considered "very low" proficiency. 

In 2018, Thailand ranked 64th out of 88 countries studied in the report with a score of 48.54, while in 2017 it ranked 53rd out of 80 countries with a score of 49.7.

Thailand has the third lowest score in Southeast Asia, behind Indonesia and ahead of Myanmar and Cambodia, and ranked 17th out of 25 countries in Asia.

By region, central and northern Thailand had slightly higher English proficiency than the Northeast and the South. Bangkok has the highest level of English proficiency in Thailand followed by Nonthaburi province, Chiang Mai, Chonburi and Khon Kaen.

Men in Thailand scored slightly above women in the report, rating 48.68 and 47.59, respectively.

Singapore ranked fifth in the world, the highest in Asia and behind four wealthy Northern European countries with the Netherlands at the top. 

The report warns that countries such as Thailand and Cambodia with economies that rely heavily on tourism could suffer from lack of English proficiency. 

The English Proficiency Index is based on an analysis of 2.3 million English tests administered by EF Education First. The report found English proficiency to be improving worldwide, however, in Asia it has remained stagnant the past five years.