The spawning biomass of Peruvian anchoveta in a managed South American fishery zone has fluctuated due to commercial fishing pressure and environmental factors. Figure 1 shows the estimated spawning biomass of anchoveta between 1985 and 2025.
Calculate the percentage decrease in the spawning biomass of anchoveta between 1985 and 2005.
Use the equation:
percentage decrease=(biomass in 1985−biomass in 2005)biomass in 1985×100\text{percentage decrease} = \frac{(\text{biomass in 1985} - \text{biomass in 2005})}{\text{biomass in 1985}} \times 100percentage decrease=biomass in 1985(biomass in 1985−biomass in 2005)×100
Give your answer to the nearest whole number.