You can get recent savings rate information at the BEA. For the 4th quarter of 2009 the personal savings rate was just over 4%. The personal savings rate is the percentage of personal income saved, so its the total amount saved / total personal income for the nation.
The Fed has historical data on the personal savings rate going back to 1959. I plotted that data in the chart below to show the trend from 1959 to 2010.
From 1959 to 2010 the Average was 7.0%, the Median was 7.5%, the minimum was 0.8% and the maximum rate hit 14.6%. From 1959 to 1995 the rate averaged 8.4%. The average rate from 1995 to 2010 had dropped to 3.4%.