Population structure: USA in 2007, India in 2030

There is a relation between "exponential reserve" and "savings with uniform deposits".

23.12: In 2004, world natural gas resources (which include estimates of undiscovered gas) totaled 6076.5 trillion cubic feet, while annual consumption was 90 trillion cubic feet. The USGS projected then that world consumption would increase 2.2% per year through 2025.

- What was the static reserve for natural gas in 2004?

6076.5/90 ≈ 67.5 years - What was the exponential reserve for natural gas in 2004?

ln[1+(6075.5/90)(0.022)]/ln[1+0.022] ≈ ln[1+(67.5*0.022)]/ln[1+0.022] ≈ ln[2.485]/ln[1.022] ≈ 0.9103/0.02176 ≈ 41.8 years - What considerations may affect the above answers over time?

Answers will vary.