Why has population growth dramatically increased over the past few centuries?

There are many factors which contribute to the growth in population. Some could be, but not limited to:
  - Enhancement in Technology. Medical care and food. Meaning G/S increases. Production increases.
  - Discovery of new vaccinations. 
  - Clean water.
People in general are becoming healthier, due to these. 
People are also becoming smarter. Learning more about what they should and shouldn't do. Think about the what wiped the Ancient Romans. The lack of knowledge "lead"  to their distinction. See what I did there? lol