There is a statistic for everything and 99% percent of the time these stats are right. If you search any industry or field and google the probability of success then you going to be greatly disheartened. Whether you want to be a successful actor, sports star, entertainer, writer or entrepreneur - you're going to go through the ringer and the stats are mounted against you. The beginning is an uphill climb because you cannot imagine even how much further you have to go and whether you'll ever see the summit.
Many budding authors are often faced with this dilemma, should I go the self publishing route? A process that is getting simpler by the day, or should I seek to get traditionally published? A significantly more arduous process, that entails finding an agent that will know how to submit the proper pitch to publishing houses that stands head and shoulders above the ever mounting pile that publishers have to sift through.