The question about happiness is phrased in the survey as follows:
On a scale from 1 to 10, can you indicate to what extent you see yourself as a happy person? 1 stands for completely unhappy and 10 for completely happy.
Those with a score of 7 or higher are regarded as happy. Those filling in a score of 9 or 10 are considered to be very happy, while those rating their happiness with a score of 4 or lower are classified as unhappy.
How perceived happiness and other features such as health, education and marital status are interrelated and how they affect each other cannot be determined on the basis of these figures.