Go visit a decent public library & look for the following resources

* Historical Atlas, that had information about population and land use at various times in history … this will get you total #s of people who lived in various geographies at various times in history

* Encyclopaedia … this will help you calculate percentages of people needed to work in food supply chain, given various technological eras

* BOOK OF FACTS … take a look at several different ones to find those organized to be most helpful to this research effort.

For example, the Reader’s Digest Book of facts has a section on key dates in world history.

Now for this research, you are not interested in Kings, Politics, War, new nations, revolutions etc. the sub-section of relevance to you includes Socian and Religious history, and timing of Science, Inventions, Medicine

year 600 estimated world population 237 million

650 … Persians using windmills, Europe not until 1100

year 700 Feudalism starts in Europe

868 – first printed book, in China … various later improvements developed

around 1200 Feudalism rises in Asia, collapse of Mayan civilization & rise of Incas

1340 world population estimated at 378 million

1347-51 Black Death kills 1 person in 4 in Europe

1348-55 Plague in Egypt

1603-49 Movement of Serfs restricted to boost farm production by slaves in Eastern Europe

1665-66 Great Plague

1712 first practical steam engine

1750 world population estimated at 731 million

1760 birth of Industrial Revolution

Look up such topics as THE INDUSTRIAL REVOLUTION and what you are looking for is NOT farmers, because people who worked the land were not called farmers back then, they were called peasants and slaves.

Look up HISTORY OF TECHNOLOGY and what you are looking for is NOT what the technology did that was so great but what it replaced.

So for example, before canals were invented, and horses used to pull barges along, what kind of manpower was needed to transport the same amount of cargo?

Specifically study HISTORY of FARMING TECHNOLOGY to get at lists of things used in farming, then see how many people were needed to do the work before the inventions came along.

Look up THE BLACK DEATH.

Here’s a hint

1. There was a mild climate change, which meant that the rural food supply could no longer feed all the people.

2. This led to starvation all over the place, which meant the people were more vulnerable to disease.

3. The way the economy worked, the landowners got first food, then left-overs to the workers, which meant even more starvation of people who otherwise could be doing the agriculture work.

4. When it was over, one third of the people were dead.

Look up the POTATO FAMINE of IRELAND

which was deliberately caused by English landowners who were fearing a revolution in the British Empire like the one that had just happened in France