Francillion gives a figure of 317 Navy aircrew lost in the 12 year period due to hostile action. From other causes of death - 2,430 Naval personnel.
Can't find total figures for Naval sorties - but Linebacker I alone was 23,652 tactical sorties against the North. Highest monthly figures for the early 70's is listed at around 3,300 to 4,800 sorties per month.