Fig. 2
From: Cross-border movement, economic development and malaria elimination in the Kingdom of Saudi Arabia
National GDP per Capita (US$) (Black line) [13], national under five mortality per 1000 live births (Blue Line) [14], and percentage of surface area where the night-time light (NTL) index is greater than 35 in the malarious areas of Jazan and Aseer regions (Brown Line). The amount of NTL, representing a qualitative scaled measure of electric light seen from space, is measured on a 0- to 63-point scale, with dense light at night measured by a measure in excess of 35 [18]. The proportion of the malaria-risk surface area of Aseer and Jazan provinces covered by intense NTL (> 35) each year between 1993 and 2013