The chart shows the development of three companies from 1990s to 2000s in the area of make refrigerator.
We can find from 1990 to 2000 the time of three companies making a refrigerator all declined. And the company A and the company C were sharper than company B. So from 1990 to 2000 the rank of which company use more less time on making refriferator had a big change. We can expict maybe the efficency of company C will over company B after 2 years ago.
In 1990, the company A and the company C manufacture a refrigerator need to use 30 hours and 35 hours. After 10 years ago the company A only spand more than 22 hours making a refrigerator and the company C can use less 30 hours to make a refrigerator.
But the vary of the company B was not very obiversely. From 1990 to 2000 the time of making a refrigerator that company B need only decrised a little, which from close 25 hours to closer 25 hours but not over the 25 hours at last.
