35% Download Failure

I have a file available for downloading on my site. I noticed that my bandwidth after moving to DH 3 months ago went up a lot. Looking at my stats, I see 2455 out of 7039 (35%) download attempts were only partial downloads.

I'm not super knowledgable about web hosting issues. I don't really understand what the problem is. What causes so many failed downloads? When I download it, it seems to work fine for me.

Do others notice this kind of download failure rate? Is there a name for this problem? What can I do about it?

What's disturbing is that many of these people understandably give up and never get a complete dl. :-(

PS:
To calc the failure rate, I combined the daily stats logs into a file: "all.log".
cat all.log | grep filename.zip | wc -l
This gives 7039 total download attempts. A successful download is 4070556 bytes.
cat all.log | grep 4070556 | wc -l
This gives 4584 complete downloads. Subtracting these gives 2455 incomplete downloads.

Could 35% (or part of them) of folks decide to cancel the download, because it takes longer than they want to wait, etc.?

Cheers,

BobS

In reply to:
cat all.log | grep filename.zip | wc -l

Or, more simply:
% grep -c filename\.zip all.log