The line graph below shows US consumers' average annual expenditures on cell phone and residential phone services between 2001 and 2010.

This

illustration shows us the evolution of the money spent each year on cell phones and residential phone services from 2001 to 2010. Looking from an

overall

perspective, we can observe that the annual expenditures on cell phones have significantly increased during that period of time, unlike residential lines services that have had an important decrease. The cost per year of cell phone facilities has known a very constant rise between these 9 years, from approximately $200 in 2001,

then

400 in 2004,

then

600 in 2007, to

finally

reach the amount of $800 in 2010. The strongest jump occurred in the first cohort with an almost 45-degree angle. Meanwhile, the residential lines service annual expenditure has not been known to a similar growth. In fact, it has declined, from almost $700 in the first bracket, after that, in 2007 it was 500 and eventually $400 in 2010.

However

, it did not fluctuate a lot during the first 5 years, since the difference between 2001 and 2006 is just about $130.