[= per cent]
About 40 percent of the solar energy is concentrated in the region ......
an increase of 5% $\langle$a 5% increase$\rangle$ in the cost of living
The quantity $A$ was greater by a mere 20%.
Quarterly sales rose by 9% compared with the same period in 2007.
% increase on previous year [in a diagram caption]
Firms employing over 1000 people accounted for 50% of total employment. [= represented 50%]
Subsidies on these commodities total 25 per cent of the budget.