Go for Summary Report and follow the steps to create a formula field to display the percentage you require.
Create a custom summary formula
1. Go to the report type category, then double-click Add Formula.
2. Enter a unique name to the formula as you want it to appear on your report.
3. In the "Description" field, enter a brief description about the formula.
4. From the "Format" picklist, select Percent.
5. Under "Decimal Places," select the number of decimal places to be displayed.
6. Select the Display Area where the calculated formula should be displayed – select Grouping1 to calculate percentage according to rows.
7. Build your formula:
To display the percentage of fields by grouping at a summary level, select the RowCount to consider total number of rows in each grouping and use the formula structure PARENTGROUPVAL(summary_field, grouping_level)
Complete Formula: RowCount / PARENTGROUPVAL(RowCount, GRAND_SUMMARY)
Source Link: https://help.salesforce.com/HTViewSolution?id=000193514