Cialis has been popular ever since its introduction in the market as a cure for erectile dysfunction in men. With a fast and long lasting effect, Cialis proved to be a tough competition for Viagra, which had previously ruled the market. Generic Viagra sales increased by leaps and bounds after its approval in 2003. Generic Cialis sales have maintained their growth margin despite the flooding of the market by generic drugs and other branded competitors such as Levitra and Viagra. Statistically speaking, the Generic Cialis sales have increased by approximately thirty percent in 2007 as compared to 2006. This is enough to show that the popularity of Cialis is increasing. In the previous years 2005 and 2006, Generic Cialis sales were an estimated $ 750 million and one billion US dollars respectively. Even in its first year, Generic Cialis sales were approximately around 200 million US dollars. Seeing the trend of market growth and the high amount of Generic Cialis sales, one cannot deny that Cialis has outstripped every other ED curing medication available in the market. Apart from its efficacy, the growth in sales can also be attributed to the excellent marketing strategy of Eli Lilly, the pharmaceutical company that manufactures Cialis.