after Mexico, to receive an invitation to join the Organisation for Economic Co-operation and Development (OECD). Bachelet signed the accession agreement in January 2010, but it formally became a member in May 2010, after she had left office. Popularity Bachelet enjoyed an approval rating above 50% for her first three months in office, during the so-called "honeymoon period". Her popularity fell during the student protests that year, hovering in the mid-40s. In July she had a disastrous public relations incident when a group of residents she was visiting in the southern city of Chiguayante who were affected by a landslide berated her publicly on television, accusing her of using their tragedy to boost her falling popularity. One woman demanded that she leave the scene so rescue efforts could continue. In July, after only four months in office, Bachelet was forced to reshuffle her cabinet, in what was the fastest ministerial adjustment since 1990. Bachelet's popularity dipped further in her second year, reaching a low of 35% approval, 46% disapproval in September 2007. This fall was mainly attributed to the Transantiago fiasco. That same month she had a second negative incident when a group of earthquake and tsunami victims she was visiting in the southern region of Aisén received her bearing black flags and accused her of showing up late. The city mayor, who told Bachelet to "go to hell", later apologized. Over the following 12 months, however, Bachelet's approval ratings did not improve. At the onset of the global financial crisis in September 2008 Bachelet's popularity was at 42%, but gradually her job approval ratings began to rise. When she left office in March 2010 her popular support was at a record 84%, according to conservative polling institute Adimark GfK. The Chilean Constitution does not allow a president to serve two consecutive terms and Bachelet endorsed Christian Democratic Party candidate Eduardo Frei Ruiz-Tagle for the December 2009 election. Political interregnum In April 2010, Bachelet inaugurated her own think-tank, "Fundación Dialoga". Its headquarters are located in Providencia, a suburb of Santiago. Bachelet is a member of the Club of Madrid, the world's largest forum of former heads of state and government. Since 2010 she has also been a member of the Inter-American Dialogue, the leading think tank on Western Hemisphere relations and affairs, and served as the organization's co-chair. On 14 September 2010, Bachelet was appointed head of the newly created