The publication of this model in his book De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres) just before his death in 1543 was a major event in the history of science, triggering the Copernican Revolution and making an important contribution to the Scientific Revolution.
World market prices for dairy products The average world market price of butter in 1981-2006 was US$1 580/ton, fluctuating between US$1 000/ton and US$2 000/ton. It shot up to US$2 886/ton in 2007 and, in the first six months of 2008, increased further to US$4 021/ton.
The US Bureau of Labor Statistics (US BLS) publishes the average price of a gallon of milk each month. The price is the average price charged in grocery stores within large US cities. You can see the recent prices for milk and many other consumer food items at the BLS website. As of this month (Jan 2015) the average price is $3.76 per gallon. During the past decade, the lowest average monthly price was $3.00 per gallon. And the highest was $3.96 per gallon. In small towns with low costs of living, especially near dairy farms, you can find lower prices.