This is a very straightforward question that deserves a straightforward answer. When forming a response to this type of question, you should always make sure that you answer in complete honesty. You should never attempt to provide an answer that is deceptive. At the same time, this is not a question where you need to go into a lot of detail. In fact, the fewer details you give with this type of question, the better.
The interviewer could be seeking to find out a variety of information by posing this type of question. It could be that they are really interested in hiring you and want to find out whether you have applied for a lot of other jobs and whether they might lose out on the opportunity to hire you. Also, they could be asking because they want to find out whether you would be a good fit for the position they are offering. If you are applying for a position as a waitress but you respond to this question by answering that you have applied for six other jobs as a receptionist, it will become very clear quite rapidly that your real interest lies in working in an office environment and not in a restaurant. As a result, the interviewer would typically assume that you are not really interested in working as a waitress and would be off to the first receptionist job you could find.
The key to handling this question well is to make sure that you keep your response focused on the job for which you are applying and what you can do to benefit that company or organization. In other information that you provide can simply be distracting and that is something that should be avoided. If you feel that you must provide additional details you might simply state that you are applying for positions within the same industry or field and leave it at that. Another way to handle the question is to say that you are applying for jobs where you will be able to utilize your skills to benefit the employer. Since most people have a range of different skills this will easily cover you in the event that you are applying for jobs that are in different fields or that are vastly different from the one for which you are interviewing.