Distance and rate of all contacts with out-of-hours service. Relationship between distance (kilometres) from population centroid of municipality and casualty clinic and rate of all contacts with Arendal out-of-hours service (per 1000 inhabitants per year). Each point represents rate in one municipality for one year. Regression curve (black line) for ln transformed data with 95% confidence interval (grey lines). Ln(contact rate) = 5,92 – 0,009*distance (km). N = 50, R2 = 0.95, p < 0.001.