### Database Schema:
CREATE TABLE country (
	origin	INTEGER	NULL	PRIMARY KEY,
	country	TEXT	NULL
);

CREATE TABLE price (
	ID	INTEGER	NULL	PRIMARY KEY,
	price	REAL	NULL
);

CREATE TABLE production (
	ID	INTEGER	NULL	PRIMARY KEY,
	model_year	INTEGER	NULL	PRIMARY KEY,
	country	INTEGER	NULL,
	foreign key (ID) references data (ID),
	foreign key (country) references country (origin),
	foreign key (ID) references price (ID)
);

CREATE TABLE data (
	ID	INTEGER	NULL	PRIMARY KEY,
	mpg	REAL	NULL,
	cylinders	INTEGER	NULL,
	displacement	REAL	NULL,
	horsepower	INTEGER	NULL,
	weight	INTEGER	NULL,
	acceleration	REAL	NULL,
	model	INTEGER	NULL,
	car_name	TEXT	NULL,
	foreign key (ID) references price (ID)
);

### User's Query:
Please list all the years in which the car model Chevrolet Impala was introduced in the market.

### Extra Knowledge:
year refers to model_year; Chevrolet Impala refers to car_name = 'chevrolet impala'
SELECT DISTINCT T1.model_year FROM production AS T1 INNER JOIN data AS T2 ON T1.ID = T2.ID WHERE T2.car_name = 'chevrolet impala'