Differences among mobile phone consumers

Please indicate your year at university (1,2,3,4,etc):

  1. 2
  2. 2
  3. 4
  4. 3, last one
  5. 3
  6. 2
  7. 2
  8. 1 (why is there no option like n/a if i do not want to answer or do not have information?)
  9. 3
  10. 2