Year	Measure
1800	601.2
1820	613.8
1870	682.7
1890	914.8
1900	1048
1910	1194
1913	1241
1929	1418
1950	1532
1951	1598
1952	1601
1953	1666
1954	1715
1955	1807
1956	1825
1957	1942
1958	2030
1959	2113
1960	2220
1961	2239
1962	2313
1963	2392
1964	2474
1965	2564
1966	2660
1967	2760
1968	2860
1969	2957
1970	3066
1971	3189
1972	3313
1973	3478
1974	3491
1975	3504
1976	3518
1977	3533
1978	3549
1979	3567
1980	3592
1981	3611
1982	3631
1983	3652
1984	3673
1985	3692
1986	3716
1987	3739
1988	3763
1989	3791
1990	3825
1991	2718
1992	2497
1993	2717
1994	2919
1995	3286
1996	3570
1997	3193
1998	3585
1999	3928
2000	4195
2001	4476
2002	4604
2003	4855
2004	5115
2005	5369
2006	5652
2007	5958
2008	6366
2009	6551
2010	6746
2011	6914
2012	6969
2013	7059
2014	7200
2015	7343
2016	7489
2017	7638
2018	7790