On the occasion of the King's eightieth birthday tomorrow, state broadcaster NRK has commissioned an opinion poll (external link) from Norstat on whether Norway ought to be a monarchy or not. The poll finds that 81 % favour a monarchy, while 15 % want a republic and 4 % are undecided. Interestingly, support for the monarchy is highest among younger people. 85 % of those in their thirties support the monarchy, while 82 % of those under thirty do so.
This may be compared with the result of a similar poll undertaken by Norstat for NRK at the time of the bicentenary of Norway's independence in the spring of 2014, which found 82 % in favour of the monarchy (the decrease from 82 to 81 % is within the margin of error). If I recall, an opinion poll around the time of King Olav's death and King Harald's accession in 1991 found 87 % in favour of the monarchy, while the lowest support measured was 59 % in 2000, when there had been a number of controversies during the preceding years.