Do Dead People Outnumber Living, Or Vice Versa?

There sure are a lot of people on planet Earth - a whopping 7 billion and counting. But how does this number, which of course represents the number of people now alive, compare to the number of people who have ever lived?

Is it really true, as some folks maintain, that the number of people now alive is greater than the number of people who have lived and died since the dawn of Homo sapiens?