Fig. 2

The evolving risk network properties over five years from 2013 to 2017. The 2013 network is the largest and also contains most edges. However, it is not the one with the highest density, since 2015 and 2017 networks are much smaller and with a large number of edges. Generally, 2013, 2015 and 2017 networks have relatively high average degrees, degree assortativity coefficients, average clustering coefficients, and max clique sizes and relatively low diameters and average shortest path lengths