The quantity of visitors(indexes are given in millions) to 4 national museums in the USA are illustrated on the provided table,consisting of 3 5-year-time periods.(2005,2010,2015) and additionally outlining the percentage changes of visitors throughout those periods.
Overall, throughout the given time Air and Space national museum is steadily possessing the highest number of visitors.Natural history museum shares the similar numbers.By contrast, American Indian museum accounts for completely opposite pattern,obtaining the lowest proportion both at the beginning and the ending of the given time period.American history museum is average between Natural history and American Indian museums.
Air and Space museum is 6.1 and 8.3 in 2005 and 2010 respectively,witnessing 36 percent rise from 2005 to 2010 ,while Natural History museum makes up for smaller digits,more specifically 5.6 and 6.8 , having 20 percent rise in the same period of time.Nevertheless, they both are equal by 2015 holding 6.2 and both have experienced the decrease.
Figures for the American History museum are higher than American Indian museum’s however are far smaller compared with the two highest ones.2005 , 2010 ,2015 are 3.0 ,4.2 , 3.6 respectively, all in all being relatively sustainable , experiencing 14 percent fall.
Lastly, the American Indian museum has been having the downward trend throughout the three forth of a decade , possessing the lowest figures and being 1.1 with 15 percent plummet at the end.