On 28 May 1975 James Whetter left MK to form the Cornish Nationalist Party which was campaigning for full Cornish independence. The party declined in the 1980s and was close to collapse by 1990. It did not contest the 1984 European Parliament election; it received 1.9% of the vote in Cornwall and West Plymouth in the 1989 election. During this period, the party focussed on its opposition to the creation of a South West England region. It also campaigned against the construction of a nuclear station at Luxulyan and proposals to increase house-building in Cornwall. In 1988, MK established the Campaign for a Cornish Constituency, which won the support of Cornwall County Council, all the district authorities, several Cornish organisations and three of Cornwall's five MPs. The campaign was well-publicised, attained national attention, and collected over 3,000 signatures in three months. Loveday Jenkin was elected its leader in 1990. The party's vote share declined further to 1.5% of the vote in the 1994 European Parliament election, in the new constituency of Cornwall and West Plymouth. In 1996, MK published 'Cornwall 2000 - The Way Ahead', its most detailed manifesto to date. On 4 October 1997, at the Mebyon Kernow National Conference, Jenkin was replaced by Dick Cole as the leader of MK.
Question: How many years did the party decline until it was close to collapse?
Answer: 10