def html_table_header_row(data):
    """
    >>> html_table_header_row(['administrators', 'key', 'leader', 'project'])
    '\\n\\t<tr><th>Administrators</th><th>Key</th><th>Leader</th><th>Project</th></tr>'
    >>> html_table_header_row(['key', 'project', 'leader', 'administrators'])
    '\\n\\t<tr><th>Key</th><th>Project</th><th>Leader</th><th>Administrators</th></tr>'
    """
    html = '\n\t<tr>'

    for th in data:
        title = th.replace('_', ' ').title()
        html += '<th>{}</th>'.format(title)

    return html + '</tr>'