Detailed Instructions: This task involves creating answers to complex questions, from a given passage. Answering these questions, typically involve understanding multiple sentences. Make sure that your answer has the same type as the "answer type" mentioned in input. The provided "answer type" can be of any of the following types: "span", "date", "number". A "span" answer is a continuous phrase taken directly from the passage or question. You can directly copy-paste the text from the passage or the question for span type answers. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words. A "number" type answer can include a digit specifying an actual value. For "date" type answers, use DD MM YYYY format e.g. 11 Jan 1992. If full date is not available in the passage you can write partial date such as 1992 or Jan 1992. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words.
Q: Passage: The surrender of Candia ended the four and a half centuries of Venetian rule in Crete, and brought the Ottoman Empire to its temporary territorial zenith. At the same time, the cost and casualties incurred during this prolonged war contributed greatly to the decline of the Ottoman state during the latter 17th century. On the other hand, Venice had lost its greatest and most prosperous colony, its pre-eminent trading position in the Mediterranean had diminished, and its treasury was exhausted, having spent some 4,253,000 ducats on the defense of Candia alone. To all this, the Dalmatian gains were insufficient compensation. Upon his return to Venice in 1670, Morosini was tried on charges of insubordination and treason, but was acquitted. Fifteen years later, he would lead the Venetian forces in the Morean War, where the Republic attempted, for the last time, to reverse its losses and reestablish itself as one of the major powers of the Eastern Mediterranean. During that war, in 1692, a Venetian fleet attempted to retake Candia, but failed. The last Venetian strongholds off Crete fell in the last Turkish-Venetian War in 1715. Crete would remain under Ottoman control until 1897, when it became an autonomous state. The island continued under nominal Ottoman suzerainty until the Balkan Wars. In their aftermath, the Ottoman Sultan dropped any claim on the island, and on 1 December 1913 it was formally united to Greece. Following the fall of Candia, fears rose that the Ottomans would attack Malta. In 1670, the Order of St. John began to improve the island's defences with the construction of the Cottonera Lines and Fort Ricasoli.
Question: How many years after Crete became an autonomous state did it formally unite to Greece?
Answer type: Number
A:
16.