According to this worldometer website in April 2017 we are now 7.5 billion humans on Spaceship Earth. Here is an extract from the rich source of demographic data:
World Population Milestones
10 Billion (2056)
The United Nations projects world population to reach 10 billion in the year 2056.
8 Billion (2023)
World population is expected to reach 8 billion people in 2023 according to the United Nations (in 2026 according to the U.S. Census Bureau).
7.5 Billion (2017)
The current world population is 7.5 billion as of April 2017  according to the most recent United Nations estimates elaborated by Worldometers. The term “World Population” refers to the human population (the total number of humans currently living) of the world.