asserting that it diminished its own identity. In 2002, New Zealand prime minister Helen Clark formally apologised for New Zealand's role in the Spanish influenza outbreak in 1918 that killed over a quarter of Samoa's population and for the Black Saturday killings in 1929. On 7 September 2009, the government changed the rule of the road from right to left, in common with most other Commonwealth countries - most notably countries in the region such as Australia and New Zealand, home to large numbers of Samoans. This made Samoa the first country in the 21st century to switch to driving on the left. At the end of December 2011, Samoa changed its time zone offset from UTC−11 to UTC+13, effectively jumping forward by one day, omitting Friday, 30 December from the local calendar. This also had the effect of changing the shape of the International Date Line, moving it to the east of the territory. This change aimed to help the nation boost its economy in doing business with Australia and New Zealand. Before this change, Samoa was 21 hours behind Sydney, but the change means it is now three hours ahead. The previous time zone, implemented on 4 July 1892, operated in line with American traders based in California. In October 2021, Samoa ceased daylight saving time. In 2017, Samoa signed the UN treaty on the Prohibition of Nuclear Weapons. In June 2017, Parliament amended Article 1 of the Samoan Constitution to make Christianity the state religion. In May 2021, Fiamē Naomi Mataʻafa became Samoa's first female prime minister. Mataʻafa's FAST party narrowly won the election, ending the rule of long-term Prime Minister Tuila'epa Sa'ilele Malielegaoi of the Human Rights Protection Party (HRPP), although the constitutional crisis complicated and delayed this. On 24 May 2021, she was sworn in as the new prime minister, though it was not until July that the Supreme Court ruled that her swearing-in was legal, thus ending the constitutional crisis and bringing an end to Tuila'epa's 22-year premiership. The FAST party's success in the 2021 election and subsequent court rulings also ended nearly four decades of HRPP rule. In August 2022, Samoa’s Legislative Assembly reappointed Tuimaleali’ifano Vaaletoa Sualauvi II as the Head of State for a second term of five years. Government and politics The 1960 constitution, which formally came into force with independence from New Zealand in 1962, builds on the British pattern