Question: How much of the US national debt is owned by the country of the philosopher who accurately described evaporation?

full_context: Document 1: National debt of the United States: On November 7, 2016, debt held by the public was $14.3 trillion or about 76% of the previous 12 months of GDP. Intragovernmental holdings stood at $5.4 trillion, giving a combined total gross national debt of $19.8 trillion or about 106% of the previous 12 months of GDP; $6.2 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest of which were Japan and China at about $1.09 trillion for Japan and $1.06 trillion for China as of December 2016.
Document 2: National debt of the United States: As of April 30, 2018, debt held by the public was $15.3 trillion and intragovernmental holdings were $5.7 trillion, for a total or ``National Debt ''of $21 trillion. Debt held by the public was approximately 77% of GDP in 2017, ranked 43rd highest out of 207 countries. The Congressional Budget Office forecast in April 2018 that the ratio will rise to nearly 100% by 2028, perhaps higher if current policies are extended beyond their scheduled expiration date. As of December 2017, $6.3 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest being China (about $1.18 trillion) then Japan (about $1.06 trillion).
Document 3: Han dynasty: Some important texts were created and studied by scholars. Philosophical works written by Yang Xiong (53 BC – 18 AD), Huan Tan (43 BC – 28 AD), Wang Chong (27–100 AD), and Wang Fu (78–163 AD) questioned whether human nature was innately good or evil and posed challenges to Dong's universal order. The Records of the Grand Historian by Sima Tan (d. 110 BC) and his son Sima Qian (145–86 BC) established the standard model for all of imperial China's Standard Histories, such as the Book of Han written by Ban Biao (3–54 AD), his son Ban Gu (32–92 AD), and his daughter Ban Zhao (45–116 AD). There were dictionaries such as the Shuowen Jiezi by Xu Shen (c. 58 – c. 147 AD) and the Fangyan by Yang Xiong. Biographies on important figures were written by various gentrymen. Han dynasty poetry was dominated by the fu genre, which achieved its greatest prominence during the reign of Emperor Wu.
Document 4: Han dynasty: Evidence of Han-era mechanical engineering comes largely from the choice observational writings of sometimes disinterested Confucian scholars. Professional artisan-engineers (jiang 匠) did not leave behind detailed records of their work. Han scholars, who often had little or no expertise in mechanical engineering, sometimes provided insufficient information on the various technologies they described. Nevertheless, some Han literary sources provide crucial information. For example, in 15 BC the philosopher Yang Xiong described the invention of the belt drive for a quilling machine, which was of great importance to early textile manufacturing. The inventions of the artisan-engineer Ding Huan (丁緩) are mentioned in the Miscellaneous Notes on the Western Capital. Around 180 AD, Ding created a manually operated rotary fan used for air conditioning within palace buildings. Ding also used gimbals as pivotal supports for one of his incense burners and invented the world's first known zoetrope lamp.
Document 5: Copernican heliocentrism: Copernican heliocentrism is the name given to the astronomical model developed by Nicolaus Copernicus and published in 1543. It positioned the Sun near the center of the Universe, motionless, with Earth and the other planets orbiting around it in circular paths modified by epicycles and at uniform speeds. The Copernican model departed from the Ptolemaic system that had prevailed for centuries, placing Earth at the center of the Universe, and is often regarded as the launching point to modern astronomy and the Scientific Revolution.
Document 6: National debt of the United States: On November 7, 2016, debt held by the public was $14.3 trillion or about 76% of the previous 12 months of GDP. Intragovernmental holdings stood at $5.4 trillion, giving a combined total gross national debt of $19.8 trillion or about 106% of the previous 12 months of GDP. As of December 2017, $6.3 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest of which were Japan (about $1.06 trillion) and China (about $1.18 trillion).
Document 7: Han dynasty: Han-era astronomers adopted a geocentric model of the universe, theorizing that it was shaped like a sphere surrounding the earth in the center. They assumed that the Sun, Moon, and planets were spherical and not disc-shaped. They also thought that the illumination of the Moon and planets was caused by sunlight, that lunar eclipses occurred when the Earth obstructed sunlight falling onto the Moon, and that a solar eclipse occurred when the Moon obstructed sunlight from reaching the Earth. Although others disagreed with his model, Wang Chong accurately described the water cycle of the evaporation of water into clouds.
Document 8: History of science: Geology existed as a cloud of isolated, disconnected ideas about rocks, minerals, and landforms long before it became a coherent science. Theophrastus' work on rocks, Peri lithōn, remained authoritative for millennia: its interpretation of fossils was not overturned until after the Scientific Revolution. Chinese polymath Shen Kua (1031–1095) first formulated hypotheses for the process of land formation. Based on his observation of fossils in a geological stratum in a mountain hundreds of miles from the ocean, he deduced that the land was formed by erosion of the mountains and by deposition of silt.
Document 9: Bessemer process: A system akin to the Bessemer process has existed since the 11th century in East Asia. Economic historian Robert Hartwell writes that the Chinese of the Song Dynasty innovated a ``partial decarbonization ''method of repeated forging of cast iron under a cold blast. Sinologist Joseph Needham and historian of metallurgy Theodore A. Wertime have described the method as a predecessor to the Bessemer process of making steel. This process was first described by the prolific scholar and polymath government official Shen Kuo (1031 -- 1095) in 1075, when he visited Cizhou. Hartwell states that perhaps the earliest center where this was practiced was the great iron - production district along the Henan -- Hebei border during the 11th century.
Document 10: National debt of the United States: As of July 31, 2018, debt held by the public was $15.6 trillion and intragovernmental holdings were $5.7 trillion, for a total or ``National Debt ''of $21.4 trillion. Debt held by the public was approximately 77% of GDP in 2017, ranked 43rd highest out of 207 countries. The Congressional Budget Office forecast in April 2018 that the ratio will rise to nearly 100% by 2028, perhaps higher if current policies are extended beyond their scheduled expiration date. As of December 2017, $6.3 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest being China (about $1.18 trillion) then Japan (about $1.06 trillion).
Document 11: National debt of the United States: As of July 31, 2018, debt held by the public was $15.6 trillion and intragovernmental holdings were $5.7 trillion, for a total or ``National Debt ''of $21.3 trillion. Debt held by the public was approximately 77% of GDP in 2017, ranked 43rd highest out of 207 countries. The Congressional Budget Office forecast in April 2018 that the ratio will rise to nearly 100% by 2028, perhaps higher if current policies are extended beyond their scheduled expiration date. As of December 2017, $6.3 trillion or approximately 45% of the debt held by the public was owned by foreign investors, the largest being China (about $1.18 trillion) then Japan (about $1.06 trillion).
Document 12: Sun: Observations of sunspots were recorded during the Han Dynasty (206 BC–AD 220) by Chinese astronomers, who maintained records of these observations for centuries. Averroes also provided a description of sunspots in the 12th century. The invention of the telescope in the early 17th century permitted detailed observations of sunspots by Thomas Harriot, Galileo Galilei and other astronomers. Galileo posited that sunspots were on the surface of the Sun rather than small objects passing between Earth and the Sun.Arabic astronomical contributions include Albatenius' discovery that the direction of the Sun's apogee (the place in the Sun's orbit against the fixed stars where it seems to be moving slowest) is changing. (In modern heliocentric terms, this is caused by a gradual motion of the aphelion of the Earth's orbit). Ibn Yunus observed more than 10,000 entries for the Sun's position for many years using a large astrolabe.
Document 13: Wang Chong: Wang Chong (; 27 – c. 100 AD), courtesy name Zhongren (仲任), was a Chinese meteorologist, astronomer, and philosopher active during the Han Dynasty. He developed a rational, secular, naturalistic and mechanistic account of the world and of human beings and gave a materialistic explanation of the origin of the universe. His main work was the "Lunheng" (論衡, "Critical Essays"). This book contained many theories involving early sciences of astronomy and meteorology, and Wang Chong was even the first in Chinese history to mention the use of the square-pallet chain pump, which became common in irrigation and public works in China thereafter. Wang also accurately described the process of the water cycle.
Document 14: Yuan dynasty: The Yuan undertook extensive public works. Among Kublai Khan's top engineers and scientists was the astronomer Guo Shoujing, who was tasked with many public works projects and helped the Yuan reform the lunisolar calendar to provide an accuracy of 365.2425 days of the year, which was only 26 seconds off the modern Gregorian calendar's measurement. Road and water communications were reorganized and improved. To provide against possible famines, granaries were ordered built throughout the empire. The city of Beijing was rebuilt with new palace grounds that included artificial lakes, hills and mountains, and parks. During the Yuan period, Beijing became the terminus of the Grand Canal of China, which was completely renovated. These commercially oriented improvements encouraged overland and maritime commerce throughout Asia and facilitated direct Chinese contacts with Europe. Chinese travelers to the West were able to provide assistance in such areas as hydraulic engineering. Contacts with the West also brought the introduction to China of a major food crop, sorghum, along with other foreign food products and methods of preparation.
Document 15: History of science: The astronomer Aristarchus of Samos was the first known person to propose a heliocentric model of the solar system, while the geographer Eratosthenes accurately calculated the circumference of the Earth. Hipparchus (c. 190 – c. 120 BC) produced the first systematic star catalog. The level of achievement in Hellenistic astronomy and engineering is impressively shown by the Antikythera mechanism (150-100 BC), an analog computer for calculating the position of planets. Technological artifacts of similar complexity did not reappear until the 14th century, when mechanical astronomical clocks appeared in Europe.
ground_truth: about $1.18 trillion
sub_queries: Who was able to describe the process of evaporation? Answer: Wang Chong
What country was Wang Chong in? Answer: China
how much of the us national debt does China own Answer: about $1.18 trillion