Aged 16-74. IUCHAT1- Using instant messaging, i.e. exchanging messages, for example, via Skype, Messenger, WhatsApp, Viber, Snapchat
  1 - Ticked
  0 - Not ticked
  9 - Not applicable (IU=Blank or IU ne 1)

Individuals Sending messages with attached files
sum of IND_WGHT where (IUCHAT1=1)