A study by Verizon Business contends nearly 9 out of 10 data breaches could have been prevented with reasonable security measures in place.  The study also indicates the great majority (73%) result from external threats.  However, it is also pointed out that damages are usually greater from internal threats.  A summary of the study can be found at http://www.eweek.com/c/a/Security/Your-Data-Breach-Was-Probably-Avoidable/