The results released by the Ministry of Education and Training show test takers from the three northern provinces fared particularly badly in math, foreign language, history, and geography.

In math, Son La students have the lowest average score of 3.5 out of 10. Ha Giang scored slightly higher at 3.69 and Hoa Binh averages 4.14. The national average is 5.64.

Only 1.4-3.6 percent of the students in the provinces scored above eight though none got 10.

Another northern province, Nam Dinh, tops the country with 6.52 followed by Ho Chi Minh City (6.35) and Ha Nam (6.18).

Son La, Ha Giang and Hoa Binh bring up the bottom in that order in foreign language, history and geography.

Students in Vietnamese high schools learn either English or French as a foreign language, and only 0.6 percent, 0.7 percent and 1.6 percent of those in the three provinces scored above eight.

More than 886,000 students attended the national high school exam last month in nine subjects including mathematics, literature and sciences. 798,435 took the English test and others French.

HCMC students earned the highest average score of 5.78 in English, which surpassed the national average of 4.36. The second and third best performers in English are from its neighbors Binh Duong and Ba Ria-Vung Tau, with an average scores of 5.18 and 5.11. Hanoi ranks fourth with 5.01.

Across the country, only 76, or less than one per 10,000 candidates, got the maximum score of 10 for English, and 732 got zero. 

The overall top scores in the exam are by Nam Dinh (5.9), Ha Nam (5.8) and Ninh Binh (5.8) in northern Vietnam. The national average is 5.39. The country's largest cities Ho Chi Minh ranks 5th with an average score of 5.8 and Hanoi 24th with 5.5.

Fraud history

Son La, Ha Giang and Hoa Binh scored unusually high marks in the same exam in July 2018. This attracted the attention of the police, who went on to uncover that officials had fraudulently given higher scores to more than 200 students.

A number of officials have been arrested or disciplined for their involvement in the fraud, the largest ever exposed in Vietnam. Dozens of students at top universities have been expelled or have voluntarily dropped out after their correct scores were revealed.

Eight officials in Son La are awaiting trial on charges of abuse of power for taking or agreeing to take VND3.2 billion ($139,400) to give high grades to 44 students.

After the scandal came to light, many students lamented to VnExpress that it possibly deprived them of the opportunity to enter better universities.

High school exams are considered by many families in Vietnam the most stressful event of the year as their results usually decide their children's career and future paths.