math word problem (sorry it is kind of a lot)

The construction of the American railroad system is one of the country's greatest technological achievements. Between the years 1840-1890, about 161,200 miles of track were built, literally "paving the way" for economic progress and land expansion. The table shows the miles of railroad track built from the years 1855-1866.

Year:1855 | 1856 | 1857 | 1858 | 1859 | 1860 | 1861 | 1862 | 1863 | 1864 | 1865 | 1866

Miles of track built: 1654 | 3642 | 2487 | 2465 | 1821 | 1846 | 651 | 834 | 1050 | 738 | 1177 | 1716

a. Make a cumulative frequency table representing the miles of track built. Use intervals of 1000.

b. In what percent of years were fewer than 2000 miles of track built per year? Explain how you know.

c. To the nearest mile, what was the mean number of miles of track built per year for the years 1855-1866?

d. Compare your answer from Part b to the average you found in Part c. Does the answer from Part c make sense? Explain.