How much of your personal statement should be about extra curricular?

On a visit to an Oxbridge conference I was told that they did not look for any information regarding extra curricular in a personal statement and since I didn't have anything signifcant to include anyway I wrote nothing about extra-curricular activies, instead focusing on aspects of my course and why I wanted to do and qualities I possess which would help me in my studies. However, if you feel you have some great extra-curricular experiences which have helped mould you into the person you are and also which are relevant to your course, do include them but they are not as vital as many make them out to be.