What are you, 10 years old?
I expected better from you.
Well, its a little difficult to seriously take anyone who doesn't know that a trend is a collection of individual data points.
And the point that you cannot compare trends from 30 years ago with current trends means that you are a minority subscriber to the "History Does NOT Repeat Itself Club."
I'll attempt to educate you regarding Math, and why those of us that understand bother to take "snap-shots," find trends, and compare them with historical data. Perhaps an analogy will be helpful?
You might have seen Hurricane's being charted on a map?
Every day, the location of the eye of the storm is charted.
This data is used to compare the possible FUTURE PATH of the hurricane, with PREVIOUS KNOWN Paths of Hurricanes
Still with me? Wake the **** up!
Then several MODELS predicting the landfall of the hurricane can be made.
For the past two months, Hurricane Barak is more closely following the same path as Hurricane Carter than any other hurricane since 1945: More importantly, it will hit land in only 12 months, a short period of time to change direction for presidential disasters.
I really hope you get it, because I don't have more time to review 8th grade math concepts.