Received: 12 March 2019
Accepted: 7 May 2019
First Online: 15 May 2019
Ethics approval and consent to participate
: In each institution, the study was approved by the institutional research ethics committee, in accordance with local ethical regulations. Informed consent was not required because of the observational and anonymous nature of the data collection.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.