How many more pieces of mail were handled by the United States Postal Service in 199519951995 than in 196519651965? Express your answer in scientific notation.
Year Approximate number of pieces of mail handled
195019501950 4.5 \cdot 10^{10}4.5⋅10
10
4, point, 5, dot, 10, start superscript, 10, end superscript
196519651965 7.2 \cdot 10^{10}7.2⋅10
10
7, point, 2, dot, 10, start superscript, 10, end superscript
198019801980 1.0 \cdot 10^{11}1.0⋅10
11
1, point, 0, dot, 10, start superscript, 11, end superscript
199519951995 1.8 \cdot 10^{11}1.8⋅10
11
1, point, 8, dot, 10, start superscript, 11, end superscript
201020102010 1.7 \cdot 10^{11}1.7⋅10
11