LAS VEGAS—Just ahead of a CTIA Wireless 2009 keynote today by T-Mobile USA President Robert Dotson, T-Mobile USA released some usage numbers related to the G1, the first commercial handset using the Google-led Android platform.

Among T-Mobile customers who have  purchased the G1, roughly half have traded up from a basic handset. G1 customers are using data services in record volume, 50 times the data of the average voice-centric phone user, and they’re accessing the Web, engaging in social networking and connecting through Wi-Fi at an accelerated pace, the carrier says.

About 80 percent of T-Mobile G1 customers are browsing the Web on a daily basis. The majority of T-Mobile G1 owners use Facebook and YouTube at least once per week, and half of G1 customers also access Wi-Fi on a daily basis.

In February, T-Mobile rolled out an update to G1 customers, including several new features and software updates such as Google Search by voice, Google Latitude and support for priced applications on Android Market.   

On average, T-Mobile G1 customers each have downloaded more than 40 applications from Android Market.  Four out of five G1 customers download applications at least once per week from Android Market.