Tourism has become one of the largest sectors of the Spanish economy, representing nearly 10 percent of Gross Domestic Product (GDP), and relegating traditional activities like fishing and agriculture to a secondary place [1]. Spain is still the second largest earner worldwide and the first in Europe (US$ 60 billion). According to the World Tourism Organization, Spain is also the fourth most visited country in the world after France, the United States and China [2]. Regarding the two key tourism indicators-international tourist arrivals and international tourism receipts-Spain ranks fourth (with 56.7 million arrivals) and second (with 59.9 million receipts) respectively.