How can I calculate percentage in improvement in the future from past results?

I had 51% approval rating in 2009 then a 46 % approval rating in 2010 which means I had a 5% improvement. How can I calculate a 5% improvement for 2011.How can I calculate percentage in improvement in the future from past results?
Did you mean a 51% rate in 2009 or 2010?

An increase from 46% to 51% is an improvement of 10.9%.

So in 2011, you could expect an approval rating of 56.6%.How can I calculate percentage in improvement in the future from past results?
One percent increase in sales means that the activity is growing. ... The size of the increase can help you better predict future production ... wanted to calculate the percentage increase in sales the previous year, ... Step 2 multiplied by 100 to find the percentage increase in sales. ...

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