Duration of the expansion before a recession

The expansion in the United States that began in 2010 has been very long. To a lesser degree, this is also the case in the euro zone, where the expansion got underway in 2012. In the past, the average duration of expansion s preceding recession was seven to eight years in the United States and five to six years in the euro zone. The current expansion is therefore already abnormally long, and no recession is expected in the short term. What accounts for the abnormal duration of the expansion that began after the 2008-2009 crisis? The main explanation is well known: there is no inflation and interest rate s are not rising .