### 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:
What is the average number of respondents per survey between 2014 and 2019?

### Extra Knowledge:
respondents and 'users' are synonyms; average number = avg(count(userID(SurveyID = 2014)), count(userID(SurveyID = 2019)))
SELECT CAST(COUNT(SurveyID) AS REAL) / 5 FROM Answer WHERE SurveyID BETWEEN 2014 AND 2019