11. The graph below shows the number of cases of measles that occurred in the world between 1980 and 2010 - Scottish Highers Human Biology - Question 11 - 2016

The vaccination rate was approximately 30% when there were 3-5 million cases of measles.

To calculate the percentage decrease:

1. Find the number of cases in 1995 and 2010 from the graph.

   • Number of cases in 1995: approximately 2.5 million.
   • Number of cases in 2010: approximately 0.3 million.

2. Use the formula for percentage decrease: ext{Percentage Decrease} = rac{ ext{Old Value} - ext{New Value}}{ ext{Old Value}} imes 100 ext{Percentage Decrease} = rac{2.5 - 0.3}{2.5} imes 100 = 88\%.

People who have not been vaccinated are still protected due to herd immunity. This occurs when a significant portion of the population is vaccinated, reducing the overall spread of the disease. Consequently, even unvaccinated individuals have a lower risk of exposure.

One reason is the presence of malnutrition and poverty, which can affect access to healthcare and medical resources necessary for vaccination programs.

In 2010, the global population was 6900 million. The vaccination rate was approximately 90%. Thus, the number of people vaccinated is:

$6900 ext{ million} imes 0.90 = 6210 ext{ million}$

Therefore, the number of people who had not been vaccinated is: $6900 ext{ million} - 6210 ext{ million} = 690 ext{ million}$.

The graph shows a significant decrease in the number of measles cases from 2005 to 2010, suggesting that with continued efforts in vaccination, measles could be eliminated. If the trend continues, as indicated, where cases decreased by around 300,000, it is plausible to forecast that there will be no cases by 2020.