yen is governed by the desire of foreigners to buy goods and services in Japan and by their interest in investing in Japan (buying yen-denominated real and financial assets). Since the 1990s, the Bank of Japan, the country's central bank, has kept interest rates low to spur economic growth. Short-term lending rates have responded to this monetary relaxation and fell from 3.7% to 1.3% between 1993 and 2008. Low interest rates combined with a ready liquidity for the yen prompted investors to borrow money in Japan and invest it in other countries (a practice known as carry trade). This has helped to keep the value of the yen low compared to other currencies. International reserve currency The special drawing rights (SDR) valuation is an IMF basket of the world's major reserve currencies, including the Japanese yen. Its share of 8.33% as of 2016 has declined from 18% as of 2000. Historical exchange rate Before the war commenced, the yen traded on an average of 3.6 yen to the dollar. After the war the yen went as low as 600 yen per USD in 1947, as a result of currency overprinting in order to fund the war, and afterwards to fund the reconstruction. When MacArthur and the US forces entered Japan in 1945, they decreed an official conversion rate of 15 yen to the USD. Within 1945–1946: the rate tanked to 50 yen to the USD because of the ongoing inflation. During the first half of 1946, the rate fluctuated to 66 yen to the USD and eventually plummeting to 600 yen to the dollar by 1947 because of the failure of the economic remedies. Eventually, the peg was officially moved to 270 yen to the dollar in 1948 before being adjusted again from 1949 to 1971 to 360 yen to the dollar. Beginning in 2022 the Yen rate has become increasingly weaker with each passing month. The reasoning behind this is the US moving towards higher interest rates, while Japan remains "ultra-low". Other factors include the strength of the US economy and its labor market, while Japan continues to lag behind its peers to bring its economy back to its pre-pandemic size. Japan’s trade balance staying in the red is also likely feeding into the weaker yen. The table below shows the monthly average of the U.S. dollar–yen spot rate (JPY per USD) at 17:00 JST: See also Japan Mint