Holes in conservatory roof - is this to be expected

[njwc]

We have a multi-layer polycarbonate roof on our conservatory which is about 15 years old, and have noticed that several of the panels have one or two small holes, up to approx 10mm across, and we are wondering if this due to the age or the panels or some other issue.

The holes appear to be different ages (some look fresh but some have a little dirt etc on the broken edges) and are irregular in shape. We don't think they are impact damage because there don't appear to be any witness marks or signs of other impacts that weren't hard enough to make a hole, either on the conservatory or on the patio around it

Could this just be down to the panels getting older or could there be some other cause ?

[njwc]

Thanks for the replies. I'm confident its not teenagers or airguns but hadn't thought of hailstones; we did have some very heavy rain last week but I don't know if there was any hail in it as we weren't home at the time. I think our next step is to probably contact an installer to get an opinion about the cause and what to do about it