Please help!

A recent review of a compact disc distributor’s product line is summarized as follows:
Selling Price ($) Number of Titles Midpoint
0 to under 5 51 2.5
5 to under 10 184 7.5
10 to under 15 241 12.5
15 to under 20 1468 17.5
20 to under 25 1339 22.5
25 to under 30 255 27.5
30 to under 35 98 32.5
35 to under 40 14 37.5

I'm supposed to prove that the median is $19.59 but I can only get 20

Question

Please help!

A recent review of a compact disc distributor’s product line is summarized as follows:
Selling Price ($) Number of Titles Midpoint
0 to under 5	      51	                2.5
5 to under 10	      184	                7.5
10 to under 15	      241	                12.5
15 to under 20	      1468	                17.5
20 to under 25	      1339	                22.5
25 to under 30	      255	                27.5
30 to under 35	      98	                32.5
35 to under 40	      14	                37.5

I'm supposed to prove that the median is $19.59 but I can only get 20