Prefix 00 was reserved for international calls, while prefix 9 was assigned to special numbers, such as 9-1-1. Toll-free numbers starts with 800 followed by 7 digits while premium rate numbers starts with 900 followed by 7 digits.This numbering system was effective for some time. However, the boom of mobile phone customers since the introduction of GSM around 2000 and the expansion of metropolitan areas caused a serious shortage of available numbers. Thus many GSM-based customers have to use a number starting with 3 and many residents of San Jose province have telephone numbers starting with prefixes other than 2. Since March 20, 2008, a renewed numbering system added the prefix 2 for all landlines and 8 for all mobile phone numbers. This system was implemented in order to face the introduction of 1,5 million 3G W-CDMA due to Q1 2009. The transition to 8-digit based was heavily publicized on Costa Rican media. However, the change caused some confusion among many foreigners. Also, all calls dialed using the old 7-digit version of the phone number are automatically redirected to a voice message informing about the change. 8 digit numbers are commonly written two ways: "xxxx xxxx" or "xx xx xx xx" [ Current Costa Rican Numeration Plan