When did Hans Hartmann drive?
CREATE TABLE table_75423 (
    "Year" real,
    "Event" text,
    "Venue" text,
    "Driver" text,
    "Result" text,
    "Category" text,
    "Report" text
)
SELECT COUNT("Year") FROM table_75423 WHERE "Driver" = 'hans hartmann'
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: When did Hans Hartmann drive? ### Input: CREATE TABLE table_75423 (
    "Year" real,
    "Event" text,
    "Venue" text,
    "Driver" text,
    "Result" text,
    "Category" text,
    "Report" text
) ### Response: SELECT COUNT("Year") FROM table_75423 WHERE "Driver" = 'hans hartmann'