How much power do data centers consume?

With all the green IT stuff going around I always wondered how much power all the data centers in the US consume annually and if this a significant number? We talk about virtualization, low power consuming processors and servers, energy efficient storage devices and the list is end less. What exactly is the impact? To answer this question I did some research and ended with a rather extensive number of blogs and articles. One highly reliable report is the one from US Environmental Protection Agency (EPA). Let's talk some numbers now.

The nations servers and data centers consumed 61 billion kilowatt-hours, a electricity cost of $4.5 billion in 2006. So the check to energy companies was $4.5B. Sounds like a big number. But comparing this to the total consumption of power in the country it accounts only to 1.5%.
The total consumption by servers and data centers has only doubled since 2000 to 2006 in spite of the multi fold increase the size and number of data centers. Things have certainly become more efficient than they were in 2006.

So even though we work a lot on improving the efficiencies of data centers, we end up saving the power bill for corporations but will not make a big impact in the big picture of the energy sector of the country. How significant is a 20% saving in 1.5% of total power consumption?