--샘플 데이타는 6월 것만 있네요 ~ ^.^ 
--해당 풀이는 기본 GROUP BY로 풀 수 있는 부분 같습니다.

WITH T(REG_DT, CNT1, CNT2, CNT3, CNT4) AS (
 SELECT 20150601, 11, 0, 0, 200 FROM DUAL UNION ALL
 SELECT 20150602, 171, 0, 0, 0 FROM DUAL UNION ALL
 SELECT 20150603, 137, 0, 0, 55 FROM DUAL UNION ALL
 SELECT 20150604, 134, 213, 0, 117 FROM DUAL UNION ALL
 SELECT 20150605, 39, 0, 0, 0 FROM DUAL UNION ALL
 SELECT 20150607, 64, 0, 0, 268 FROM DUAL UNION ALL
 SELECT 20150608, 189, 0, 0, 0 FROM DUAL UNION ALL
 SELECT 20150609, 81, 0, 0, 0 FROM DUAL UNION ALL
 SELECT 20150610, 89, 0, 93, 133 FROM DUAL UNION ALL
 SELECT 20150611, 93, 0, 69, 79 FROM DUAL UNION ALL
 SELECT 20150612, 169, 0, 83, 0 FROM DUAL UNION ALL
 SELECT 20150613, 18, 0, 54, 347 FROM DUAL UNION ALL
 SELECT 20150615, 61, 0, 0, 70 FROM DUAL UNION ALL
 SELECT 20150616, 100, 0, 106, 71 FROM DUAL UNION ALL
 SELECT 20150617, 117, 0, 0, 79 FROM DUAL UNION ALL
 SELECT 20150618, 84, 0, 0, 93 FROM DUAL UNION ALL
 SELECT 20150619, 50, 0, 0, 0 FROM DUAL UNION ALL
 SELECT 20150620, 30, 0, 174, 0 FROM DUAL UNION ALL
 SELECT 20150621, 16, 0, 0, 0 FROM DUAL UNION ALL
 SELECT 20150622, 65, 95, 15, 0 FROM DUAL UNION ALL
 SELECT 20150623, 107, 299, 85, 0 FROM DUAL UNION ALL
 SELECT 20150624, 74, 138, 9, 0 FROM DUAL UNION ALL
 SELECT 20150625, 43, 110, 44, 0 FROM DUAL UNION ALL
 SELECT 20150626, 18, 0, 0, 0 FROM DUAL UNION ALL
 SELECT 20150627, 41, 0, 0, 0 FROM DUAL UNION ALL
 SELECT 20150628, 112, 0, 127, 0 FROM DUAL UNION ALL
 Select 20150629, 9, 35, 0, 0 From Dual Union All
 Select 20150630, 92, 114, 87, 0 From Dual Union All
  Select 20150701, 9, 35, 0, 0 From Dual Union All
 SELECT 201500802, 92, 114, 87, 0 FROM DUAL 
)
Select
  SUBSTR(REG_DT, 1, 6), SUM(CNT1), SUM(CNT2), SUM(CNT3), SUM(CNT4)
From
  T
Group By 
  SUBSTR(REG_DT, 1, 6)
  

1. 조건이 다르다고 개별 쿼리로 하실 필요는 없습니다.
   공통 조건은 Where 절에, 개별 조건은 Case 문으로 하여
   하나의 쿼리에서 Group By Count 하시면 됩니다.
   총합계도 필요하면 Rollup 이용
2. 불필요한 함수 사용을 줄이세요.
   널이 존재한다고 해서 무조건 NVL 해야 하는 것은 아닙니다.
3. 컬럼을 가공하여 비교하기 보다는(AND SUBSTR(reg_dt, 1, 4) = '2015')
   조건을 가공하여 비교하세요(AND reg_dt LIKE '2015%')

SELECT NVL(SUBSTR(reg_dt, 1, 6), '총합계') reg_ym
     , COUNT(CASE WHEN NVL(note, '-') NOT IN ( '한꺼번에 등록'
                                             , '경찰서 과태료 엑셀파일로 한꺼번에 등록')
            /* AND pol_sta NOT IN ('278','353','455','504','389','459','486','358','347') */
                  THEN 1 END) cnt1
     , COUNT(CASE WHEN note = '한꺼번에 등록'
                   AND pol_sta IN ('278','353','455','504','389','459','486','358','347')
                  THEN 1 END) cnt2
     , COUNT(CASE WHEN note = '경찰서 과태료 엑셀파일로 한꺼번에 등록'
                   AND pol_sta <> '278'
                  THEN 1 END) cnt3
     , SUM(cnt) cnt4
  FROM fine
 WHERE reg_id IN ('000155', '000096')
   AND reg_dt LIKE '2015%'
 GROUP BY ROLLUP(SUBSTR(reg_dt, 1, 6))
;