In 1954, under the "Charter for the Kingdom of the Netherlands", the Netherlands, Suriname and the Netherlands Antilles  became a composite kingdom. The former colonies were granted autonomy, save for certain matters including defense, foreign affairs and citizenship, which were the responsibility of the Realm. In 1969, unrest in Curaçao led to Dutch marines being sent to quell rioting. In 1973, negotiations started in Suriname for independence, and full independence was granted in 1975, with 60,000 emigrants taking the opportunity of moving to the Netherlands. In 1986, Aruba was allowed to secede from the Netherlands Antilles federation, and was pressured by the Netherlands to move to independence within ten years. However, in 1994, it was agreed that its status as a Realm in its own right could continue. On October 10, 2010, the Netherlands Antilles were dissolved. Effective on that date, Curaçao and Sint Maarten acceded to the same country status within the Kingdom that Aruba already enjoyed. The islands of Bonaire, Sint Eustatius and Saba were granted a status similar to Dutch municipalities, and are now sometimes referred to as the Caribbean Netherlands.
Question: How many years passed between the unrest in Curacao and the negotiations in Suriname?
Answer: 4