Year   APO
1948   2.013
1949   3.141
1950   2.340
1951   1.372
1952   2.106
1953   3.683
1954   2.121
1955   2.052
1956   2.603
1957   1.581
1958   1.602
1959   2.452
1960   2.803
1961   4.278
1962   4.026
1963   2.747
1964   1.463
1965   0.965
1966   1.563
1967   2.390
1968   1.106
1969  -0.118
1970   1.108
1971   1.918
1972   0.985
1973   1.757
1974   1.082
1975   1.059
1976  -0.111
1977   0.158
1978   1.571
1979   0.749
1980  -0.012
1981   0.754
1982   0.439
1983  -0.271
1984   2.039
1985   0.501
1986  -0.252
1987  -1.004
1988  -0.023
1989   0.461
1990   0.536
1991   0.661
1992  -1.716
1993  -1.354
1994   0.846
1995  -0.905
1996   0.217
1997  -1.020
1998  -0.057
1999  -0.290
2000   1.195
2001  -0.340
2002  -0.720
2003  -1.301
2004  -1.116
2005  -0.708
2006   1.343
2007   0.467
2008   0.873
2009  -0.528
2010   0.303
2011   0.924
2012   1.165
2013   1.877
2014  -0.995
2015  -1.180
2016   0.940
2017  -0.163
2018   1.814
2019   0.080
2020  -0.312
2021  -0.088
2022   1.019
2023   0.663
2024   0.331