Point prevalence of vibration-induced white finger (VWF) as a function of exposure time. The data sets from Futatsuka and Ueno [26] are shown as small asterisks, the fits to the respective data sets from Section 3.3 as a thin line and the assumed known data point from which to estimate the exposure time to reach 10% prevalence as a large asterisk. Linear interpolation from the assumed known data point is shown by the dashed line and polynomial interpolation using equation (4) up to the 4th-order with the respective parameter values from Table 1 by the thick line. The prevalence of interest (10%) is shown by the horizontal dotted line.