THE STATISTICS WERE DERIVED FROM MONTHLY REPORTS SUBMITTED BY EACH DISTRICT COURT DURING THE YEAR ENDING JUNE 30, 1978. THE TOTAL NUMBER OF GRAND JURIES INCREASED FROM 641 IN 1977 TO 659 IN 1978, WHILE THE NUMBER OF HOURS IN SESSION DECLINED FROM 47,094 TO 46,739. THE SOUTHERN DISTRICT OF NEW YORK HAD THE GREATEST NUMBER OF SESSIONS CONVENED (1931), WHILE THE DISTRICT OF COLUMBIA HAD THE HIGHEST NUMBER OF HOURS IN SESSION (4,161). MONTANA AND GUAM HAD THE LOWEST TOTALS IN EACH OF THE THREE CATEGORIES. THE GRAND JURY SESSIONS RESULTED IN 22,694 CASES INVOLVING 32,740 DEFENDANTS. THE AVERAGE NUMBER OF DEFENDANTS INDICTED PER GRAND JURY SESSION HAS DECLINED STEADILY, FROM 5.10 PER SESSION IN 1975 TO 3.67 IN 1978. FOR PETIT JURIES, 570,523 JURORS WERE AVAILABLE; 60.5 PERCENT OF THESE JURORS WERE SELECTED FOR OR SERVED ON JURY TRIALS. CORRESPONDING FIGURES FOR 1974 WERE 540,628 AND 58.3 PERCENT, RESPECTIVELY. THE PERCENTAGE OF JURORS CHALLENGED WAS 15.5; THOSE NOT SELECTED OR NOT SERVING TOTALED 24.0 PERCENT. THE PERCENTAGE OF JURORS SELECTED OR SERVING ON JURY TRIALS RANGED FROM 41.7 PERCENT IN LOUISIANA TO 86.1 PERENT IN CONNECTICUT, WHILE THAT OF CHALLENGED JURORS RANGED FROM 2.8 PERCENT IN GUAM TO 41.3 PERCENT IN LOUISIANA. THE NATIONAL JUROR USAGE INDEX (TOTAL AVAILABLE JUROR DAYS DIVIDED BY TOTAL JURY TRIAL DAYS) WAS 19.51. THE INCREASE IN THE NUMBER OF GRAND JURY SESSIONS AND THE USE OF LESS EFFICIENT PETIT JURY SELECTION TECHIQUES, EXPECIALLY IN SMALL DISTRICTS, ARE BOTH EFFECTS OF THE 1974 SPEEDY TRIAL ACT. EXPENDITURES FOR PETIT AND GRAND JURIES, EXTENSIVE SUMMARY TABLES, INDIVIDUAL PROFILES FOR THE 95 DISTRICTS, AND APPENDIXES PRESENTING A GLOSSARY AND A LIST OF U.S. DISTRICT COURTS WHICH HAVE ADOPTED RULES REDUCING THE SIZE OF CIVIL JURIES ARE INCLUDED. (CFW)