"date","value"
1956-01-01,284
1956-04-01,213
1956-07-01,227
1956-10-01,308
1957-01-01,262
1957-04-01,228
1957-07-01,236
1957-10-01,320
1958-01-01,272
1958-04-01,233
1958-07-01,237
1958-10-01,313
1959-01-01,261
1959-04-01,227
1959-07-01,250
1959-10-01,314
1960-01-01,286
1960-04-01,227
1960-07-01,260
1960-10-01,311
1961-01-01,295
1961-04-01,233
1961-07-01,257
1961-10-01,339
1962-01-01,279
1962-04-01,250
1962-07-01,270
1962-10-01,346
1963-01-01,294
1963-04-01,255
1963-07-01,278
1963-10-01,363
1964-01-01,313
1964-04-01,273
1964-07-01,300
1964-10-01,370
1965-01-01,331
1965-04-01,288
1965-07-01,306
1965-10-01,386
1966-01-01,335
1966-04-01,288
1966-07-01,308
1966-10-01,402
1967-01-01,353
1967-04-01,316
1967-07-01,325
1967-10-01,405
1968-01-01,393
1968-04-01,319
1968-07-01,327
1968-10-01,442
1969-01-01,383
1969-04-01,332
1969-07-01,361
1969-10-01,446
1970-01-01,387
1970-04-01,357
1970-07-01,374
1970-10-01,466
1971-01-01,410
1971-04-01,370
1971-07-01,379
1971-10-01,487
1972-01-01,419
1972-04-01,378
1972-07-01,393
1972-10-01,506
1973-01-01,458
1973-04-01,387
1973-07-01,427
1973-10-01,565
1974-01-01,465
1974-04-01,445
1974-07-01,450
1974-10-01,556
1975-01-01,500
1975-04-01,452
1975-07-01,435
1975-10-01,554
1976-01-01,510
1976-04-01,433
1976-07-01,453
1976-10-01,548
1977-01-01,486
1977-04-01,453
1977-07-01,457
1977-10-01,566
1978-01-01,515
1978-04-01,464
1978-07-01,431
1978-10-01,588
1979-01-01,503
1979-04-01,443
1979-07-01,448
1979-10-01,555
1980-01-01,513
1980-04-01,427
1980-07-01,473
1980-10-01,526
1981-01-01,548
1981-04-01,440
1981-07-01,469
1981-10-01,575
1982-01-01,493
1982-04-01,433
1982-07-01,480
1982-10-01,576
1983-01-01,475
1983-04-01,405
1983-07-01,435
1983-10-01,535
1984-01-01,453
1984-04-01,430
1984-07-01,417
1984-10-01,552
1985-01-01,464
1985-04-01,417
1985-07-01,423
1985-10-01,554
1986-01-01,459
1986-04-01,428
1986-07-01,429
1986-10-01,534
1987-01-01,481
1987-04-01,416
1987-07-01,440
1987-10-01,538
1988-01-01,474
1988-04-01,440
1988-07-01,447
1988-10-01,598
1989-01-01,467
1989-04-01,439
1989-07-01,446
1989-10-01,567
1990-01-01,485
1990-04-01,441
1990-07-01,429
1990-10-01,599
1991-01-01,464
1991-04-01,424
1991-07-01,436
1991-10-01,574
1992-01-01,443
1992-04-01,410
1992-07-01,420
1992-10-01,532
1993-01-01,433
1993-04-01,421
1993-07-01,410
1993-10-01,512
1994-01-01,449
1994-04-01,381
1994-07-01,423
1994-10-01,531
1995-01-01,426
1995-04-01,408
1995-07-01,416
1995-10-01,520
1996-01-01,409
1996-04-01,398
1996-07-01,398
1996-10-01,507
1997-01-01,432
1997-04-01,398
1997-07-01,406
1997-10-01,526
1998-01-01,428
1998-04-01,397
1998-07-01,403
1998-10-01,517
1999-01-01,435
1999-04-01,383
1999-07-01,424
1999-10-01,521
2000-01-01,421
2000-04-01,402
2000-07-01,414
2000-10-01,500
2001-01-01,451
2001-04-01,380
2001-07-01,416
2001-10-01,492
2002-01-01,428
2002-04-01,408
2002-07-01,406
2002-10-01,506
2003-01-01,435
2003-04-01,380
2003-07-01,421
2003-10-01,490
2004-01-01,435
2004-04-01,390
2004-07-01,412
2004-10-01,454
2005-01-01,416
2005-04-01,403
2005-07-01,408
2005-10-01,482
2006-01-01,438
2006-04-01,386
2006-07-01,405
2006-10-01,491
2007-01-01,427
2007-04-01,383
2007-07-01,394
2007-10-01,473
2008-01-01,420
2008-04-01,390
2008-07-01,410