Answer
See the picture.
Work Step by Step
Cumulative frequency for "30,000-35,999" is $21$
Cumulative frequency for "36,000-41,999" is $21+18=39$
Cumulative frequency for "42,000-47,999" is $21+18+7=46$
Cumulative frequency for "48,000-53,999" is $21+18+7+3=49$
Cumulative frequency for "54,000-59,999" is $21+18+7+3+1=50$
Cumulative frequency for "60,000-65,999" is $21+18+7+3+1+0=50$
Cumulative frequency for "66,000-71,999" is $21+18+7+3+1+0+1=51$