how many people can recollect their dreams in the morning?

Usually i think i will forgot, coz when i wake up in the morning, i am aware that i had a dream, but just can't remember what is it about. I think most of us do. But sometimes, the dream is so vivid that we could remember every detail of it. Base on the research of scientists on our dream, there are several level of sleep we can have, namely shallow sleep, deep sleep and etc. It depends on the brain activity being detected. So usually, in shallow sleep, we will forget what we dream about. But if we were in deep sleep, we can remember it even after we are awake. For those intermediate one, if we quickly recollect what was in our dream, we can remember, but if we did not flash back what we dreamt about, then we will forget it forever. It's really true, coz i do have some personal experience of it.