This study says what?
So, for some stupid reason... the number of files containing sensitive information is higher on one drive than it is on the typical corporate network? In this case.. a lot higher.
We didn't hit anywhere close to 18% on our first run through using DLP on: personal folders, personnel folders, application storage or databases. So these figures seem a bit high to me. I just called a few people and asked them what they think, and they're inline with me.
To provide a minimal fair sample, you'd need to study 100-200 companies using one drive for accurate figures. I'm thinking the companies who would allow this study to take place on their systems likely don't think security first; skewing the results. Please don't say people used some sort of survey. Surveys aren't accurate for technical information like this due to interpretation for one thing.
The blog you're getting this information from isn't even concentrating on security. It talks about the increased use of Office365. Even then it only provides figures, and doesn't provide any informative proof to back it up. Doesn't provide what type of study was done, how it was conducted and participants. Nothing for us to go... "hmmm".