Overall the number of households in the state continues to increase. This is no surprise given that we are a magnet state. In good times and bad people pack up and move to this part of the world, especially when job opportunities are plentiful. Given migration flows in recent years have been about as large as we have seen in absolute terms (not true in percentage terms), it makes sense that the number of new households are increasing quickly as well.
The latest Census data shows Oregon added just over 36,000 new households last year, the highest we have seen in the ACS data.