Density of black lines indicate the penetration of mobile phones where more than 10% of the population own one. Sparse lines represent less than 50% ownership, semi-concentrated 50% to 100%, and most dense indicate more phones than inhabitants. Countries with more than double the world's average growth rate (CAGR) of 23% from 2002 - 2007 are encircled with bright dots. There are 4 billion mobile phones, 3 times the number of landlines.