Chinese languages

ok i have this small portion of text a friend would like to see translated to english. I have no idea about the context or meaning but im fairly sure its a question, any help would be appreciated, even if you can only give the general idea. here is the text:

您的主要飛行哩程點數號碼為何

any help is greatly appreciated.

The Chinese original text is not very clear. My guess is:

What is your frequent mileage (miles) number?