Interpreting+Population+Pyramids

Population Pyramids

There are three types:
 * First is the upright pyramid. This is mainly for developing countries where birth rates are high, and so are death rates, resulting in the wide top narrow bottom shape. This is because health standards and standards of living are low, and many children die at a early age. But because of lack of birth control, the birth rate is high. [[image:http://upload.wikimedia.org/wikipedia/commons/b/b5/Population_Pyramids_for_Gambia.png]]


 * The second type is often referred to as the 'rocket' shaped pyramid. It is wide at the middle, and narrow at the top and bottom. This is often the pyramid for post baby boom periods. The babies have entered the working class, and as living standards improve, more children survive to maturity. Because of that, the people have less children, preferring to concentrate on their career. Also, one thing to note is that there are more elderly, due to the higher standard of living means longer lifespan. [[image:http://www.census.gov/cgi-bin/ipc/idbpyr.pl?cty=BD&yr=2000&maxp=3236&maxa=100&ymax=250&color=1 caption="Population Pyramid for Bermuda: 2000"]]
 * Finally is the inverse pyramid. It has a large top and a small bottom, signalling low birth rates, low death rates and long lifespans. This is usually found in very developed countries, where people prefer to have less children. This explains the narrow base. The middle, the working class, is shrinking as more of them are growing older. The top is wide as the high standard of living means many more people live till old age. This pyramid is a sign of an aging population. [[image:http://www.census.gov/cgi-bin/ipc/idbpyr.pl?cty=UK&yr=2025&maxp=2478822&maxa=100&ymax=250&color=1 caption="Population Pyramid for United Kingdom: 2025"]]