Complex sentence: By 1981, New York Telephone was making $3 million from Sports Phone over a year; 50 million calls were made to Sports Phone that year; the only Dial-it service that received more activity was the one for off-track betting.
Split into simpler sentences: By 1981, New York Telephone was making $3 million from Sports Phone over a year; 50 million calls were made to Sports Phone that year. The only Dial-it service that received more activity was the one for off-track betting.