Figure 4
Absolute numbers of SDM publications over time according to publication type. The curve was estimated in a Poisson model; with the number of non-research publications in a year and the number of research publications in a year as dependent variables (N0 and N1, respectively) and year since 1996 as an independent variable (t). N0 = exp(3.37 + 0.22 ∗ t - 0.04 ∗ t2 + 0.002 ∗ t3). N1 = exp(2.17 + 0.22 ∗ t - 0.01 ∗ t2). All coefficients P ≤ 0.001.