Definition: 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.
Input: Passage: William A. Thorpe was killed in an accident in 1918, his business continuing to operate on the island to the present day. In 1920 the Norwegian ship Spangereid caught fire and sank at her mooring at James Bay, depositing quantities of coal on the beach below the wharf. A census in 1921 showed the islands population was 3,747. The first islanders left to work at Ascension Island in 1921, which was made a dependency of St Helena in 1922. Thomas R. Bruce (postmaster 18981928) was the first islander to design a postage stamp, the 19221937 George V ship-designthis significantly contributed to island revenues for several years. South African coinage became legal tender in 1923, reflecting the high level of trade with that country. There were nine deaths from whooping cough between 1920 and 1929 and 2,200 cases of measles in 1932. The first car, an Austin 7, was imported into the island in 1929. A census in 1931 showed a population of 3,995 (and a goat population of nearly 1,500). Cable & Wireless plc absorbed the Eastern Telegraph Company in 1934. Tristan da Cunha was made a dependency of St Helena in 1938.
Question: How many years was Thomas R. Bruce a postmaster?
Answer type: Number
Output:
30.