In September 2009, Goldman Sachs published its 188th Global Economics Paper named "A United Korea?" which highlighted in detail the potential economic power of a United Korea, which will surpass all current G7 countries except the United States; including Japan, the United Kingdom, Germany and France within 30–40 years of reunification, estimating GDP to surpass $6 trillion by 2050. The young, skilled labor and large amount of natural resources from the North combined with advanced technology, infrastructure and large amount of capital in the South, as well as Korea's strategic location connecting three economic powers, is likely going to create an economy larger than some of the G7. According to some opinions, a reunited Korea could occur before 2050. If it occurred, Korean reunification would immediately raise the country's population to over 80 million. According to research by Jin-Wook Kim at Citi, reunification would require an investment of US$63.1 billion in the long term to rebuild transportation such as railroads, roads, airports, sea ports and other infrastructure like power plants, mines, oil refineries, and gas pipelines.