If the economy is now in an expansion, how long has the expansion lasted?

Answer 1

The economy switched from "recovery mode" into "expansion mode" in the middle of 2003. Economists mark this change by the growth in industrial production that really began to take off at that point, have remained high since then.

These rates began to moderate in late 2004, but remain at health levels for the most part. Remember that too much growth too quickly leads to inflation.