The decline in energy from 2003-present lines up nicely with the phase out of incandescent lights in favour of CFLs and of CFLs in favour of LEDs.
Lets say a house typically had 5 60W bulbs on for 8hrs a day, now replaced with an 8W bulb. That would be a 2 kWH reduction, which roughly corresponds to the drop shown in the data.
EDIT: actually now that I think about it, 2kWh per-household is probably less than 1kWh per-capita. It's still a good chunk though!
Lets say a house typically had 5 60W bulbs on for 8hrs a day, now replaced with an 8W bulb. That would be a 2 kWH reduction, which roughly corresponds to the drop shown in the data.
EDIT: actually now that I think about it, 2kWh per-household is probably less than 1kWh per-capita. It's still a good chunk though!