<|begin_of_text|><|start_header_id|>system<|end_header_id|>

You are an expert at identifying data availability statements in scientific text. A data availability statement describes where research data can be found or how it can be accessed.<|eot_id|><|start_header_id|>user<|end_header_id|>

Determine if the following text contains a data availability statement. Answer with 'yes' or 'no'.

Text: data underlying the findings in our study cannot be made freely available due to ethical restrictions, based on the highly sensitive nature of the data containing mortality registrations and medical assessments. data are available upon request from the belgian physical fitness study whose authors may be contacted at els.clays@ugent.be.<|eot_id|><|start_header_id|>assistant<|end_header_id|>

yes<|eot_id|>