what does the underlined mean in the following sentence?

*Last year, we strengthened our commitment to innovation by *__doubling the rate of increase __of spending for basic and applied research, compared to the rate in the year before.

Rate of increase is a mathematical term but mostly used to derive economic parameters such as rate of economic growth/inflation/population growth etc.

· The formula is: Rate of increase = Total number of increase / Total time

e.g.

Population of city A is 150000 in Year 2005 and 180000 in Year 2008.

The rate of increase is (Total number of increase-180000 – 150000=30000) / (Total time-2008 – 2005=3)

= 30000 / 3 = 10000 people per year

If you need the rate of increase per month:

30000/ (3x12) = 30000 / 36 = 833.33 people per month

Here is a chart showing growth of population in Indian sub-continent calculated from per year to per minute

Rate of Increase in Indian Population

Per Year ....................1,55,31,000

Per Month ...............12,73,033

Per Day ....................42,434

Per Hour ..................1,768

Per Minute ..............29