The reason for this is low price flights from larger relatively nearby airports like Örnsköldsvik Airport and Sundsvall-Timrå Airport and the 5-hour train connection to Stockholm (started 2012) (travel has not been reduced overall during this period, but Kramfors passengers have to a large extent chosen other routes).
The cause is low-cost flights from larger airports like Örnsköldsvik Airport and Sundsvall-Timrå Airport, coupled with a 5-hour train trip to Stockholm (initiated in 2012). Travel hasn't decreased overall during this period; however, Kramfors passengers have predominantly chosen other routes.