Year,Nigeria,Romania,Dominican Republic
1960,6.364,2.34,7.555
1964,6.362,1.96,7.186
1969,6.438,3.19,6.366
1973,6.633,2.44,5.667
1978,6.921,2.52,4.644
1982,6.799,2.17,4.014
1987,6.504,2.38,3.528
1991,6.426,1.59,3.349
1996,6.217,1.3,3.04
2000,6.124,1.31,2.869
2005,6.063,1.4,2.574
2009,5.993,1.66,2.574
2014,5.622,1.56,2.451
2018,5.021,1.76,2.397
2023,4.482,1.71,2.243