These charts show why there may be a spike in Chinese military planes flying over Taiwan’s airspace this week

Over the next few days, as one of Taiwan’s most senior politicians touches down in the United States, observers are anticipating that China could take another opportunity to flex its military muscles. China has ratcheted up military and political pressure on its democratically governed neighbour over the last three years, and has repeatedly voiced its opposition to friendly relations between Taiwan and the US. Beijing considers Taiwan part of its territory, and it hasn’t ruled out the use of force to achieve reunification. As part of China’s show of strength, its presence in the Taiwan Strait has been steadily increasing,…