Arrange the following key events in the order of their occurrence, which reflect changes in British economic policies in India during the 19th century:

1. Introduction of the Permanent Settlement by Lord Cornwallis
2. Introduction of the Ryotwari System in parts of Madras and Bombay Presidencies
3. Introduction of the Mahalwari System in parts of northern India
4. The opening of the Suez Canal, significantly boosting Indian exports to Britain