Since Global Insight's Joburg-based data collection began in 1996 (that is, annual growth rates are available from 1997), the City has shown positive real GDP growth peaking at 6,5 percent in 2002. Additionally, since 1996, the City's GDP growth rate has outpaced the national growth rate in GDP, due largely to the dominance of the fast-growing financial and business services sector in Joburg's economy, which has consistently outperformed average growth rates.
The City contributes 17 percent of the national economy's Gross Value Added (GVA) and 44 percent of Gauteng's GVA and Joburg has generally outperformed both the national and provincial economy.
However, the data indicate that the relationship between the City's growth and national growth appears to be largely counter-cyclical, meaning the city's economy slows while the national economy speeds up and vice versa.
This relationship could be partially explained by the greater relative importance of the agricultural, mining and manufacturing sector in the national economy, such that strong growth in these sectors would increase national GVA growth substantially while having little impact on City GVA growth.
It could be argued that the predominance of head offices and shareowners is likely to make income levels - and hence economic activity - in Joburg more dependent on cyclical shifts in corporate profitability than the economy as a whole. According to data published by the South African Reserve Bank, the net operating surpluses of incorporated businesses rose dramatically in 2001 and 2002, and then slowed in 2003 and 2004 - which tends to support the evidence shown above.
The key factor is that Joburg's economy has almost consistently outperformed both the national and Gauteng economies, to a considerable degree. Between 1996 and 2004, the Joburg economy grew at a real annual average rate of 4,5 percent, while Gauteng's economy expanded at a pace of 3,9 percent, and the national economy at 2,9 percent.
For the period 2000 to 2004, Joburg accelerated its real growth rate, to an average of five percent per annum.
The city's higher-than-average household income combined with strong growth in that income translates into significant purchasing power.
The Index of Buying Power (IBP) weights data around population, income and retail sales to indicate the buying power attributable to an area, as a percentage of the national total.
The City's IBP in 2004 was 0,14 indicating that 14 percent of South African demand for goods and services emanates from Joburg. The second largest consumer market in Cape Town, with an IBP of 0,11. In comparison, eThekwini commands only nine percent of demand and Nelson Mandela Metro three percent of the country's goods and services .
Expenditure in the City grew particularly strongly between 1997 and 2001 but slowed in the last three years to 2004. The high base from which expenditure growth is coming can explain this slowdown.
Nonetheless, growth remains strong by almost any standard. Even with this drop in the pace of annual growth, the City's consumer expenditure market remains the most important in the country due to its absolute size. The high level of purchasing power and growth in household income and expenditure shows a strong local support base for the City's trade sector.
Sectoral analysis of growth
Unpacking sector growth assists in understanding the performance of the City's nine major sectors in their own right and when compared to national and other urban centre trends offers a deeper picture of the drivers of the City's growth.
For each sector four key variables have been analysed: Firstly, the sector's average annual growth has been considered using the percentage change of gross value added. Secondly, each sector's contribution to the overall City's GVA has been examined. This describes the mix of the City economy and indicates trends regarding changes in the fundamental structure of the City's economy.