### Database Schema:
CREATE TABLE Question (
	questiontext	TEXT	NULL,
	questionid	INTEGER	NULL	PRIMARY KEY
);

CREATE TABLE Answer (
	AnswerText	TEXT	NULL,
	SurveyID	INTEGER	NULL,
	UserID	INTEGER	NULL	PRIMARY KEY,
	QuestionID	INTEGER	NULL	PRIMARY KEY,
	foreign key (QuestionID) references Question (questionid),
	foreign key (SurveyID) references Survey (SurveyID)
);

CREATE TABLE Survey (
	SurveyID	INTEGER	NULL	PRIMARY KEY,
	Description	TEXT	NULL
);

### User's Query:
From 2016 to 2019, how many users each year were asked the question 13?

### Extra Knowledge:
From 2016 to 2019 refer to SurveyID 2016 BETWEEN 2019; Question 13 refer to QuestionID
SELECT SurveyID, COUNT(UserID) FROM Answer WHERE QuestionID = 13 AND SurveyID BETWEEN 2016 AND 2019 GROUP BY SurveyID