2020,Vital statistics of Japan,, Volume 1 Natality Table 4.25-1 Trends in live births,percent distribution and mean birth weight by sex and birth weight (500 g groups): Japan (1) Male Note: 1) The percent distribution is for the number of live births excluding data with unspecified birth weight.    2) As birth weight was considered in 100 gram units until 1991,0.05kg was added to the calculated mean weight.      However,the survey form was revised in 1992 and the arithmetic mean value considered in 100 gram units is being used since then.    3)The figures do not correspond to those in the report before 2017 because recalculations were done due to omissions in reporting (released on March 29,2019) for 2004,2006 and 2009-2017 from prefectures. Source: Data for 1951,1955 and 1960 are based on the “Statistics on Birth Weight” in the Specified Report of Vital Statistics. ,1951,1955,1960,1970,1975,1980,1985,1990,1995,2000,2005,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019,2020 Number(Male), , , , , , , , , , , , , , , , , , , , , , , , Total,1094641,889670,824761,1000403,979091,811418,735284,626971,608547,612148,545032,559513,548994,550743,538271,531781,527657,515572,515468,502012,484478,470851,443430,430713 Under 1.0kg,53,121,207,721,448,678,1022,1151,1311,1452,1536,1619,1606,1673,1544,1624,1527,1542,1580,1424,1328,1366,1287,1313 1.0kg and over ,less than 1.5kg,1908,1807,2211,2839,2602,2269,2428,2200,2400,2593,2591,2563,2479,2525,2512,2425,2399,2283,2302,2168,2170,2009,1963,1803 1.5〜2.0kg,11498,9777,9474,9504,7912,6338,5793,5463,5880,6698,6613,6560,6384,6384,6208,6165,6162,5943,5844,5695,5583,5451,5112,4871 2.0〜2.5kg,56691,46274,41665,39328,35077,29438,27460,27181,31413,36994,35534,36710,36173,36414,35369,34846,34609,33671,33418,32406,31349,30462,28466,27256 2.5〜3.0kg,273757,215750,217187,228666,214698,184080,177886,172242,186552,202033,187674,195406,192615,194231,188316,186444,184822,181388,181536,175724,169031,163858,154664,148626 3.0〜3.5kg,524671,424672,387494,462500,456578,380149,345724,293246,278617,272538,238515,243318,238863,239005,234391,232349,230061,224140,224985,219680,212247,206613,194674,190370 3.5〜4.0kg,185219,154078,140205,217891,222942,178570,151853,110920,91705,81352,66286,66832,64877,64615,64183,62174,62639,61131,60421,59743,57668,56115,52739,51882 4.0〜4.5kg,31729,26262,20938,34925,35511,27348,21190,13451,9817,7863,5861,6055,5605,5466,5361,5384,5096,5115,5057,4852,4831,4653,4259,4327 4.5kg and over,3512,2734,1806,2967,3013,2452,1768,1009,693,553,333,339,283,305,271,260,271,275,237,228,205,253,196,206 Not stated,5603,8195,3574,1062,310,96,160,108,159,72,89,111,109,125,116,110,71,84,88,92,66,71,70,59 (Regrouped)1.0kg and over,1088985,881354,820980,998620,978333,810644,734102,625712,607077,610624,543407,557783,547279,548945,536611,530047,526059,513946,513800,500496,483084,469414,442073,429341 (Regrouped)Under 2.5kg,70150,57979,53557,52392,46039,38723,36703,35995,41004,47737,46274,47452,46642,46996,45633,45060,44697,43439,43144,41693,40430,39288,36828,35243 Percentage(Male), , , , , , , , , , , , , , , , , , , , , , , , Total,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0,100.0 Under 1.0kg,0.0,0.0,0.0,0.1,0.0,0.1,0.1,0.2,0.2,0.2,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3,0.3 1.0kg and over ,less than 1.5kg,0.2,0.2,0.3,0.3,0.3,0.3,0.3,0.4,0.4,0.4,0.5,0.5,0.5,0.5,0.5,0.5,0.5,0.4,0.4,0.4,0.4,0.4,0.4,0.4 1.5〜2.0kg,1.1,1.1,1.2,1.0,0.8,0.8,0.8,0.9,1.0,1.1,1.2,1.2,1.2,1.2,1.2,1.2,1.2,1.2,1.1,1.1,1.2,1.2,1.2,1.1 2.0〜2.5kg,5.2,5.2,5.1,3.9,3.6,3.6,3.7,4.3,5.2,6.0,6.5,6.6,6.6,6.6,6.6,6.6,6.6,6.5,6.5,6.5,6.5,6.5,6.4,6.3 2.5〜3.0kg,25.1,24.5,26.4,22.9,21.9,22.7,24.2,27.5,30.7,33.0,34.4,34.9,35.1,35.3,35.0,35.1,35.0,35.2,35.2,35.0,34.9,34.8,34.9,34.5 3.0〜3.5kg,48.2,48.2,47.2,46.3,46.6,46.9,47.0,46.8,45.8,44.5,43.8,43.5,43.5,43.4,43.6,43.7,43.6,43.5,43.7,43.8,43.8,43.9,43.9,44.2 3.5〜4.0kg,17.0,17.5,17.1,21.8,22.8,22.0,20.7,17.7,15.1,13.3,12.2,11.9,11.8,11.7,11.9,11.7,11.9,11.9,11.7,11.9,11.9,11.9,11.9,12.0 4.0〜4.5kg,2.9,3.0,2.5,3.5,3.6,3.4,2.9,2.1,1.6,1.3,1.1,1.1,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0 4.5kg and over,0.3,0.3,0.2,0.3,0.3,0.3,0.2,0.2,0.1,0.1,0.1,0.1,0.1,0.1,0.1,0.0,0.1,0.1,0.0,0.0,0.0,0.1,0.0,0.0 (Regrouped)1.0kg and over,99.5,99.1,99.5,99.8,99.9,99.9,99.8,99.8,99.8,99.8,99.7,99.7,99.7,99.7,99.7,99.7,99.7,99.7,99.7,99.7,99.7,99.7,99.7,99.7 (Regrouped)Under 2.5kg,6.4,6.5,6.5,5.2,4.7,4.8,5.0,5.7,6.7,7.8,8.5,8.5,8.5,8.5,8.5,8.5,8.5,8.4,8.4,8.3,8.3,8.3,8.3,8.2 Mean weight,3.14,3.15,3.14,3.22,3.24,3.23,3.20,3.16,3.11,3.07,3.05,3.05,3.04,3.04,3.04,3.04,3.04,3.04,3.04,3.05,3.05,3.05,3.05,3.05