Judged by the amount of time Americans sit in the dark without power each year, America's electricity grid is about 20% less reliable. Time in the dark is up from 94 to 112 minutes per year, according to the AP.
http://www.courierpress.com/news/2013/mar/06/us-power-grid-costs-rise-but-service-slipping/. See also:
In fact, the 112 minutes in the dark understates probably considerably how much time on average Americans sit in the dark each year, because the number does not include time without electricity service due to mass outages from the increasingly extreme storms like Sandy that are the new normal.
Just in the last two years, tens of millions of Americans have lost service for many hours or a day. Millions of Americans have lost service for days. And hundreds of thousands have lost service for weeks and months due to extreme storms ravaging an unprepared grid.