There are more humans alive today than have ever lived in all of human existence, I know how daft that sounds but check and you will see that it is true.
If we say the current world population is 6.5 billion and then you add on only the 1 billion people who have most recently died, how is 6.5 billion greater than 7.5 billion.
There have been various attempts to estimate the number of humans who have ever existed (you first have to decide what is a human!) - one version puts the figure around 96 billion - here.