Content includes : Over 1,010,000 records of historic music materials, indexed and bibliographically described by specialists (as of May 2015) ; A resource that is continuously growing (approximately 30,000 new records per year) ; Significant collections from libraries and archives worldwide ; Documentation primarily of music manuscripts Emphasis: originating between 1600-1800 (previously series A/II) ; An estimated 1/3 of extant music manuscripts worldwide to 1800 ; Documentation of printed music as well ; Emphasis: individual prints issued between 1600-1800 (previously series A/I) and anthologies issued between 1500 and 1550 (previously series B/I) ; Approximately 60% of all extant prints worldwide to 1800.