The popularity of Hong Kong’s chief executive has taken a major hit in a new poll from the University of Hong Kong. Chief Executive Leung Chun-ying’s approval dropped to a rating of 37.5 in the survey, losing 5.2 points from mid-December to hit a new low, the South China Morning Post reported Tuesday.

The dip in support comes amid the ongoing mystery around the missing bookseller Lee Bo and his vanishing employees. The disappearance of the bookseller, who was last seen at the company’s warehouse Dec. 30, has caused some in the city to fear Chinese authorities. Leung drew criticism last week when he urged the bookseller to reveal himself, South China Morning Post reported.

The new rating marked a low point for Leung since he took control of Hong Kong in 2012. And it was just 2.5 points above the all-time lowest score for a chief executive of the city. That honor is held by Tung Chee-hwa, whose support dropped to 35 points after a pro-democracy march rocked the city in 2003.

The march involved 500,000 people walking through the streets of Hong Kong to demonstrate against a controversial national security bill that people thought would hurt their freedoms. Following the march, Tung was forced to kill the bill and he subsequently stepped down from his position in 2005.

The chief executive who served immediately before Leung, Donald Tsang Yum-kuen, received a similarly low score of 38.5 in 2012.

Leung saw his own round of massive protests in 2014 when tens of thousands took to the streets to demand fully democratic elections for the city's chief executive. They called for Leung to resign and police used tear gas on the demonstrators, which led to violent altercations and public support for the protestors, the BBC reported.

Leung’s low popularity score was accompanied by a plunging net approval rate, the South China Morning Post reported. That score dropped 11 points to minus 44 percent.

As the chief executive’s numbers dropped, three other officials have seen their popularity ratings go down as well. Chief Secretary Carrie Lam Cheng Yuet-ngor had a score of 52.1, Financial Secretary John Tsang Chun-wah had 59.3 and Justice Secretary Rimsky Yuen Kwok-keung had 45 points Tuesday.

The university officials who administered the public opinion poll said a political figure’s credibility would be in danger if their rating fell below 45 points. The survey included 1,013 Hong Kong residents and was conducted between Jan. 4 and Jan. 6.