What year was the most recent US Open championship?
CREATE TABLE table_19864 (
    "Outcome" text,
    "Year" real,
    "Championship" text,
    "Surface" text,
    "Partner" text,
    "Opponents in the final" text,
    "Score in the final" text
)
SELECT MAX("Year") FROM table_19864 WHERE "Championship" = 'US Open'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What year was the most recent US Open championship? ### Input: CREATE TABLE table_19864 (
    "Outcome" text,
    "Year" real,
    "Championship" text,
    "Surface" text,
    "Partner" text,
    "Opponents in the final" text,
    "Score in the final" text
) ### Response: SELECT MAX("Year") FROM table_19864 WHERE "Championship" = 'US Open'