TurnItIn Percentage High

So I just submitted my first report for a particular subject and I also checked in with TurnItIn for plagiarism and it happened to come back with a 43% similarity percentage which I was surprised about. I overlooked the report and it only highlighted my reference section and not my actual work. My lecturer also said in our last class that it was normal for references, etc to get highlighted.
Just wondering if I should be worried about this?
Thanks.

You should not be worried.

For any given subject there is a finite number of sources which can be referenced. So it's highly likely that you're referencing the same sources which multiple people have referenced in the past. This is why your lecturer has told you this is quite normal.

Was is odd, however, is that your reference section consumes about 43% of your whole paper. Is that right? So a 10-page paper contains about 5.7 pages of content and 4.3 pages of references?

I should have mentioned that the paper I submitted was not the final report, but a research task where I needed to find articles and reference them.

That explains the high proportion of references to content then! Even more of a reason not to be worried.