Table 4.

Topological statistics of the pig trade networks in 2011.

Production system (area)	Topological statistics
	# of nodes	Density	% of isolates	Clustering coefficient	Mean kin (range)	Mean kout (range)
Small producers (Bulgaria)a	1,349	6.7 × 10−4	0.0	0.049	0.9 (0–7)	0.9 (0–35)
Extensive (Spain—Extremadura)	14,097	2.1 × 10−5	67.7	0.038	0.3 (0–70)	0.3 (0–27)
Intensive (France—Côtes-d’Armor)	2,396	5.4 × 10−4	20.4	0.066	1.3 (0–236)	1.3 (0–83)

k_in, in-degree; k_out, out-degree.

^aIsolates were excluded for Bulgaria: initially there were 28,729 premises, of which 95.3% were isolated premises.