What are the real statistics?

Okay, just in the past two weeks, I have had conversations with parents of two dyslexic kids who have not been able to get an accurate diagnosis and one first grade teacher who feels certain that one of her students is dyslexic but can not get the school to test and diagnosis him.  I wonder just how many people there are out there that have struggled with dyslexia and yet don't know it or can not get an accurate diagnosis.  With all the advances in medicine and technology, why is it so difficult to get a diagnosis for dyslexia?  The diagnosis alone made such a huge difference for my family.  Just to be able to see the beast for what it is instead of stabbing in the dark revolutionized our life.  How many more people out there would be set on the road to freedom just by knowing that there is a name for what they are struggling with and they are not alone in this struggle?  I just do not understand why a diagnosis is so hard to come by?