Electricity Consumption The table below gives the retail sale of electricity (in billions of kilowatt-hours) for the residential and commercial sectors of the United States. Year 2000 2003 2006 2009 2012 2015 Residential (billions of kilowatt-hours) 1,192 1,276 1,400 1,420 1,402 1,390 Let a represent time (in years) with x=0 corresponding to 2000, and let y represent the corresponding residential sales. Find the quadratic regression equation for the data y= R(x) = ax2 + bx + c with a rounded to the nearest hundredth (2 decimal places), b rounded to the nearest tenth (1 decimal place), and c rounded to the nearest integer. (See the Regression page in the Getting Started module for ways of computing a regression model.) Use this quadratic model to answer the questions below.