user: Question: What day did the platform sell 9.87 million units?
Columns: ['Rank', 'Title', 'Release Date', 'Franchise', 'Developer(s)', 'Platform', 'Units sold (in Millions)']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Pokémon Red / Green / Blue Version', '27 February 1996', 'Pokémon', 'Nintendo / GameFreak', 'Game Boy', '31.37']
SQL:

assistant: SELECT "Release Date" FROM "Table" WHERE "Units sold (in Millions)" = '9.87';