Students learn in microeconomics that the demand curve for a good, which shows the relationship between the price of a good and the quantity of the good that consumers demand-i.e. are willing, ready, and able to purchase-has a negative slope.
The UNICEF estimates that an average of 353,000 babies are born each day around the world. The crude birth rate is 18.9 births per 1,000 population or 255 births globally per minute or 4.3 births every second (as of Dec. 2013 estimate).
Many instances of anophthalmia also occur with microphthalmia. A recent study in the UK indicated that anophthalmia and microphthalmia had a combined average of 1 in every 10,000 births. The annual rate of occurrence of anophthalmia/microphthalmia in the United States is about 780 children born/year.