user
Instruction
Answer the question based on the provided table.


Table
Table Title: cannabis and gross domestic product prices, 2018
Table Content:
<table border="1" cellspacing="0">
<tr> <td rowspan="2">  </td> <td> first quarter </td> <td> second quarter </td> <td> third quarter </td> <td> fourth quarter </td> </tr>
<tr> <td colspan="4"> statscannabis average price </td> </tr>
<tr> <td> all cannabis </td> <td> 6.82 </td> <td> 6.93 </td> <td> 7.09 </td> <td> 7.39 </td> </tr>
<tr> <td> of which: legal cannabis </td> <td> . </td> <td> . </td> <td> . </td> <td> 9.70 </td> </tr>
<tr> <td> of which: illegal cannabis </td> <td> . </td> <td> . </td> <td> . </td> <td> 6.51 </td> </tr>
<tr> <td>  </td> <td colspan="4"> implicit price indexes </td> </tr>
<tr> <td> gross domestic product at market prices </td> <td> 107.7 </td> <td> 108.0 </td> <td> 108.6 </td> <td> 107.7 </td> </tr>
<tr> <td> of which: cannabis-related </td> <td> 81.2 </td> <td> 81.4 </td> <td> 82.6 </td> <td> 83.5 </td> </tr>
<tr> <td> of which: other </td> <td> 108.0 </td> <td> 108.3 </td> <td> 108.9 </td> <td> 108.0 </td> </tr>
<tr> <td>  </td> <td colspan="4"> implicit price indexes, percentage change </td> </tr>
<tr> <td> gross domestic product at market prices </td> <td> 0.5 </td> <td> 0.3 </td> <td> 0.6 </td> <td> -0.8 </td> </tr>
<tr> <td> of which: cannabis-related </td> <td> 1.2 </td> <td> 0.2 </td> <td> 1.5 </td> <td> 1.1 </td> </tr>
<tr> <td> of which: other </td> <td> 0.5 </td> <td> 0.3 </td> <td> 0.6 </td> <td> -0.8 </td> </tr>
</table>


Question
in the fourth quarter of 2018, how mush was the average price of illegal cannabis lower than the price of legal cannabis?


Answer Format
The final answer should be concise and use the following format:
```json
{
    "answer": [
        "answer1",
        "answer2",
        ...
    ]
}
```
rule
["0.328866"]