The International Telecommunication Union (ITU) is a United Nations agency dealing with information and communication technology issues.  The World Telecommunication/ICT Indicators Database contains time series data for the years 1960, 1965, 1970 and annually from 1975-2008 for around 100 sets of telecommunication statistics (updated) covering telephone network size and dimension, mobile services, quality of service, traffic, staff, tariffs, revenue and investment.

Data Provider: United Nations International Telecommunication Union
Description of Data Provider: United Nations Agency
Data Source: World Telecommunications / ICT Indicators Database (ITU)
Type: Official Data
Frequency: 1960, 1965, 1970 and annually from 1975-2008
Public Access:  Commercially Available
Website: http://www.itu.int/net/home/index.aspx

Indicators from source