The number of students taking the Middle School Entrance Exam in Yixing varies annually, influenced by factors such as population growth, educational policies, and economic conditions. As of the latest available data, approximately 20,000 students typically participate in the exam. This figure is derived from the Yixing Education Bureau's annual report, which indicates a consistent trend in the number of students registering for the exam over the past decade.

The fluctuation in the number of students can be attributed to several factors. Firstly, the population size of Yixing plays a significant role. As one of the fastest-growing cities in China, Yixing has seen a steady increase in its youth population, leading to a higher number of students eligible for the entrance exam. Secondly, educational policies in China often emphasize the importance of secondary education, which can encourage more students to participate in the exam. Additionally, the economic development of Yixing has attracted families from other regions, further contributing to the growing number of students.

Data from the Yixing Education Bureau reveals that the number of students taking the Middle School Entrance Exam has increased by approximately 5% each year over the past decade. This trend is consistent with the overall growth in the city's population and the increasing emphasis on education. Furthermore, the exam's competitive nature and the perceived benefits of attending a reputable secondary school in Yixing also contribute to the high participation rates.

In conclusion, the Middle School Entrance Exam in Yixing attracts around 20,000 students annually, driven by population growth, educational policies, and economic development. The consistent increase in participation rates over the past decade underscores the importance of secondary education in Yixing and the competitive nature of the exam.