Two major U.S. retail companies began installing electric car charging stations outside stores in two states this month, adding privately financed infrastructure that analysts say will be critical for the growth of the electric vehicle market in the U.S. In Texas, Walgreens, working with NRG Energy, began installing the first of 18 rapid charging stations outside stores in the Dallas/Fort Worth area. According to company officials, the stations will offer a high-speed charger that can add 30 miles of range after just 10 minutes of charging time, and so-called Level 2 chargers that can add 25 miles of range per hour of charging time. NRG, which is installing the systems, will offer charging packages from $49 to $89 per month. Earlier this month, Simon Property Group, Inc., the largest owner and manager of retail property space in the U.S., added its first self-serve electric charging station outside a shopping mall in Orlando, Fla., and is currently adding another at the Stanford Shopping Center in Palo Alto, Calif. President Obama said earlier this year that he wants to see 1 million electric cars on U.S. roadways by 2015, and experts say the growth of the market depends on a network of charging stations nationwide.