Answer is $2006$
No need to do any calculations ,just observe the bar chart.
Here $\%$ increase is asked, so just check for previous year & next year pair, where you can find maximum positive change.
Consider year $2006$.
Red Bar is above $3$ steps than $2005$ AND Blue Bar is $3$ steps more than $2005$, total $ = 3 + 3 = 6$, it's maximum.