Mergers and acquisitions reached a 10-year high.

In spite of a second-half slowdown, both the number of mergers reported and the total value of such acquisitions increased last year, W. T. Grimm & Co. said. The merger consultant and publisher said acquisitions totaled 2,543 in 1984, up slightly from 2,533 in 1983. This was the highest annual count since 1974, when 2,861 deals were recorded. Grimm said megadeals in the oil and gas industry early in 1984 spread to other industries. Total dollar value paid for all transactions providing a purchase price in 1984 rose 67% to a record-breaking $122.2 billion.