Japan's asset price bubble collapse in 1991 led to a period of economic stagnation known as the "lost decade", sometimes now extended as a "lost 20 years." From 1995 to 2007, GDP fell from $5.33 trillion to $4.36 trillion in nominal terms. From the early 2000s, the Bank of Japan set out to encourage economic growth through a novel policy of quantitative easing. Debt levels continued to rise in response to the Global Financial Crisis in 2007-08, the Tōhoku Earthquake in 2011, and the COVID-19 pandemic beginning in late 2019. As of 2021, Japan has significantly higher levels of public debt than any other developed nation, standing at 266% of GDP. 45% of this debt is now held by the Bank of Japan. The Japanese economy faces considerable challenges posed by an aging and declining population, which peaked at 128 million in 2010 and has fallen to 125.9 million as of 2020. Projections suggest the population will continue to fall, and potentially drop below 100 million by the end of the 21st century.