When did the British hand-over sovereignty of Hong Kong back to China?

The British handed over sovereignty of Hong Kong back to China in 1997 because it was the year when the 99-year lease of the New Territories, which were on a long-term lease from China since 1898, was set to expire. In accordance with the Sino-British Joint Declaration signed in 1984, Hong Kong was returned to China under the principle of "One Country, Two Systems," allowing the region to maintain its capitalist economic system and a high degree of autonomy for 50 years after the handover.