List all the years in order of appearance, separated by commas.

Context: Grosvenor Museum is a museum in Chester, Cheshire, in the United Kingdom. It is recorded in the National Heritage List for England as a designated Grade II listed building. Its full title is The Grosvenor Museum of Natural History and Archaeology, with Schools of Science and Art, for Chester, Cheshire and North Wales. It takes its name from the family name of the Dukes of Westminster, who are major landowners in Cheshire. The museum opened in 1886, it was extended in 1894, and major refurbishments took place between 1989 and 1999. Its contents include archaeological items from the Roman period, paintings, musical instruments, and a room arranged as a Victorian parlour.

Answer: 1886, 1894, 1989, 1999