Complex sentence: During the 1960s, he had several more top forty hits until 1969 when his song "Dizzy" went to No.1 on the UK Singles Chart as well as to Billboard's No.1 in the USA.
Split into simpler sentences: During the 1960s, he had several more top forty hits. In 1969, his song "Dizzy" went to No.1 on the UK Singles Chart as well as to Billboard's No.1 in the USA.