Database Software

Hello 1 have a Test-table in 10G with 1 LOB-segment of 1700 Mb , 1743 records with PDF's

In 11G 11.1.0.7 i create a table with SCEUREFILE in ASSM tablespace, the table is partitioned.
When 1 insert the 1743 records wioth PDF's the total segmentsize is even 1900 MB...???

Why are my PDF's not more compressed?

CREATE TABLE SNL_SCAN.DOCUMENTEN_LGE
(
OWNER VARCHAR2(50 BYTE),
COMPANY VARCHAR2(50 BYTE),
SCAN_ID VARCHAR2(50 BYTE) NOT NULL,
DOCUMENT BLOB,
FILENAME VARCHAR2(255 BYTE),
CONTENT_TYPE VARCHAR2(50 BYTE),
ORDER_DATE DATE,
SCAN_DATE DATE,
STATUS VARCHAR2(1 BYTE),
CUSTOM_01 VARCHAR2(50 BYTE),
CUSTOM_02 VARCHAR2(50 BYTE),
CUSTOM_03 VARCHAR2(50 BYTE),
CUSTOM_04 VARCHAR2(50 BYTE),
CUSTOM_05 VARCHAR2(50 BYTE),
CUSTOM_06 VARCHAR2(50 BYTE),
OWNER_ID NUMBER(9) NOT NULL,
SCAN_PLACE_DATE DATE DEFAULT sysdate
)
TABLESPACE SCAN_DATA
PCTUSED 0
PCTFREE 10
INITRANS 1
MAXTRANS 255
PARTITION BY RANGE (SCAN_DATE)
INTERVAL( NUMTOYMINTERVAL(1,'MONTH'))
(
PARTITION DOCUMENTEN_LGE_200605 VALUES LESS THAN (TO_DATE(' 2006-06-01 00:00:00', 'SYYYY-MM-DD HH24:MI:SS', 'NLS_CALENDAR=GREGORIAN'))
LOGGING
COMPRESS FOR ALL OPERATIONS
TABLESPACE SCAN_DATA
LOB (DOCUMENT) STORE AS SECUREFILE
( TABLESPACE SCAN_DATA
ENABLE STORAGE IN ROW
CHUNK 8192
RETENTION
NOCACHE
COMPRESS HIGH
STORAGE (
INITIAL 64K
NEXT 1M
MINEXTENTS 1
MAXEXTENTS UNLIMITED
PCTINCREASE 0
FREELISTS 1
FREELIST GROUPS 1
BUFFER_POOL DEFAULT
)
)
PCTFREE 10
INITRANS 1
MAXTRANS 255
STORAGE (
INITIAL 64K
NEXT 1M
MINEXTENTS 1
MAXEXTENTS UNLIMITED
BUFFER_POOL DEFAULT
)
)
COMPRESS FOR ALL OPERATIONS
NOCACHE
NOPARALLEL
MONITORING
ENABLE ROW MOVEMENT;