How much dust is inside a brand new lens?

I recently acquired a lens that looked brand new. How much dust is inside a brand new lens? With the naked eye could see only one particle, a tiny fleck on the element that was immediately in front of the aperture. Then I took a really bright light, held the aperture open and shined it through the lens from the back. Under such harsh lighting it was possible to see quite a few miniscule particles of dust that did not show up when you looked in from only one end of the lens, either front or back, even with a light. Curious, I looked at quite a few other lenses I have in the same way and virtually all of them had some amount of microscopic dust on the interior elements that was only visible if you shine a bright light through from the back. Even more curious, I opened a brand new Sony 50mm f/1.8 that can't have been manufactured more than four months ago, and I was able to see some microscopic dust on the interior elements of this brand new lens as well (not as much as in the used lenses, but it was there). From this I conclude that if you look closely enough, with bright enough light, and from the right angle, you will find some sort of dust on every lens. I've tested many of the lenses on my Sony A700 and can say that what dust there is on most lenses has absolutely no discernible influence on image quality. Thick coatings of dust that make the glass foggy will of course degrade image quality, but a few particles that you can only see with a flashlight will have no influence.