Calligraphy and painting appraisal, how much is a flat foot of calligraphy and painting in Yu Zhixue?

According to Yu Zhixue's personal index data, in the spring of 2002, Yu Zhixue traditional Chinese painting entered the auction market, and the price per square foot was 992 yuan. At that time, the works of many domestic painters had reached two or three thousand yuan per square meter. However, since the fall of 2003, the price per square foot of his works has risen to 3434 yuan. And then keep it at two or three thousand yuan per square meter. From spring to autumn in 2005, the price per square foot of his works rose from 6858 yuan to 10 108 yuan. Since then, the price has gradually dropped, hovering below 4500 yuan. This year, the spring auction has increased significantly, reaching 9045 yuan per square meter, and the autumn auction suddenly rose to 157676 yuan.