The pyramid below shows how many players there are at every level of hockey from the NHL down to mites.The numbers were compiled a couple years ago and possibly are a bit light for the lower levels as USA Hockey is agressively promoting hockey at the youngest levels.
European players are not considered in this exercise however they are present in the professional and colligate levels thus making it even harder for US born players to make the college and professional teams.
Notice that the numbers drop at each level above pee wees for each birth year that is being counted.
As a parent you need to know what the odds are for your child to "live the Dream". The odds are not good and frankly if he or she has the talent it will be recognized. If your child is an average player then help them set realistic goals.
Hockey is a great game to play and for 99% of the players that is all it ever will be. Kids are young only once and should play many sports and enjoy many activities along with hockey.
During the off season go fishing, on vacation, play other sports and take at least a month off from all sports to rest.