The decline appears to be accelerating. In March 2017, the last month for which Inverness reported numbers (they appear to have missed the April deadline, there are no figures for Inverness in the April report for any of the 3 international routes), DUB fell 26% on the previous March, with only about 27 passengers per day.
GVA more than doubled (up 101%) to overtake DUB with 876 passengers
despite merely being a once-a-week seasonal service; AMS is up 54% to 3572 pax.