The Chinese estimates are interesting. It's actually between 40 million and 80million that has been estimated to have been killed between 1949-1975. These are just estimates and could be totally wrong.
The real numbers are known by the government in Beijing, but of course they're not releasing that information. I would guess that if the real numbers were below the estimates the government might say so. It also means that there is a high chance that the numbers are much worse than the estimates as the government has made sure they stay hidden.
I think it's also interesting that the government managed to hide from the rest of the world that the worst famine in history was happening until 1980. I mean no one in the west had any idea about this.
This is an old and kind of ugly graphic I whipped up to show the discrepancy between male and female populations in China:
Vertical axis is age, horizontal axis is population (thousands), light red is males, dark red and light orange (at the top) are females.
You can clearly see the effects of the Great Leap Forward on there. You'd be hard-pressed to find a 49-year-old in China today.