end in that year, billions USD NON-OECD proportion² of total infrastructure spend in that year, % OECD proportion² of total infrastructure spend in that year, % Note: This is a highly approximate model with many assumptions and first estimates. (To create a reliable model would be a medium/large project in itself.) N.B.: Model assumes a simple incremental forward investment over 12 month cycle of capex spent in previous year adds this year's subscribers. 1. Includes inflator factor for historic levels of more expensive legacy OECD infrastructure of $1 500 per fixed line (broadband and PSTN) and $1 000 mobile, for 2 billion subscribers (as 1 billion subscribers each for mobile and fixed) for 2005-20 and assuming average of previous and current capex per new user over last 5 years. 2. Assume new subscribers ratio is quickly reflected in the installed base value so proportion of infrastructure maintenance of installed base for non-OECD has same values each year. INFRASTRUCTURE TO 2030: TELECOM, LAND TRANSPORT, WATER AND ELECTRICITY - ISBN 92-64-02398-4 - © OECD 2006 2. TELECOMS INFRASTRUCTURE TO 2030 total investment reduces. This is due to the impacts of technology costs, which are expected to reduce sharply with the effects of both lower-cost yet enhanced technology but at volume pricing, the two factors having a net deflationary impact over 20 years of some 80% of gross costs (equivalent to a non-compound, simple linear drop of around 4% per annum); those costs are comprised of renewal and maintenance of existing plus new build investment. New build investment itself is expected to drop in magnitude as saturation of the user population is reached and SO the major portion of investment is taken up with renewals and support maintenance. Note that this investment estimate table is highly debateable, being given over 25 years, with many assumptions for the dependent variables being open to challenge, and SO is at best only an outline indication of investment patterns. Migration to a new infrastructure model It would 