How many years entered service when there were 13 locomotives?
CREATE TABLE table_77567 (
    "Locomotive" text,
    "Type" text,
    "Builder" text,
    "Builder's No." real,
    "Built" real,
    "Entered service" real,
    "Withdrawn" text
)
SELECT COUNT("Entered service") FROM table_77567 WHERE "Locomotive" = '13'
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: How many years entered service when there were 13 locomotives? ### Input: CREATE TABLE table_77567 (
    "Locomotive" text,
    "Type" text,
    "Builder" text,
    "Builder's No." real,
    "Built" real,
    "Entered service" real,
    "Withdrawn" text
) ### Response: SELECT COUNT("Entered service") FROM table_77567 WHERE "Locomotive" = '13'