Spam - small businesses giving up?

An Australian government study showed that close to 30% of small and medium sized companies in the country don't bother installing anti-spam software and rather fight the spam "manually".

Other data of the study showed that more 50% of the SMEs would receive more than 5 spam messages a day - but that 36% of businesses believed staff spent more than 30 minutes a day dealing with spam. Spam cost 25 per cent of businesses more than $5,000 (it is not clear if this relates to Australian Dollars or US$) a year.

However, we believe that the amount of spam must either be much larger or that the receivers actually open the mail and read it, before deciding to delete the mail.  Why d we believe this?

Well, the study says that a minimum of 5 mails are received and that the executives deal more than 30 minutes a day dealing with it.  Does this make sense? Okay, spam decreases productivity, and our inbox receives more than 5 mails a day - we wish, it would be just 5 mails a day.

We don't want to underestimate the amount of spam that is being received, but show that the study either didn't include reasonable ranges in their questions or that it just doesn't make too much sense.