I got curious, so I made a graph with the average of sizes above 10KB per version (to exclude the checksum files).
2006 1.0 1 MB |x
2006 1.60 1 MB |x
2003 1.73 2 MB |x
2003 1.80 1 MB |x
2003 2.04 2 MB |x
2003 2.26 2 MB |x
2003 2.27 3 MB |x
2003 2.27-newpy 3 MB |x
2003 2.28 3 MB |x
2003 2.28a 3 MB |x
2003 2.28c 2 MB |x
2003 2.30 3 MB |x
2003 2.31 3 MB |x
2003 2.31a 3 MB |x
2004 2.32 3 MB |x
2004 2.33 4 MB |x
2004 2.33a 4 MB |x
2004 2.34 5 MB |x
2004 2.35 5 MB |x
2004 2.36 5 MB |x
2005 2.37 6 MB | x
2005 2.37a 6 MB | x
2005 2.39 7 MB | x
2005 2.40 7 MB | x
2006 2.41 7 MB | x
2006 2.42 10 MB | x
2007 2.43 11 MB | x
2007 2.44 12 MB | x
2007 2.45 13 MB | x
2008 2.46 15 MB | x
2008 2.47 15 MB | x
2008 2.48 17 MB | x
2008 2.48a 15 MB | x
2009 2.49 19 MB | x
2009 2.49a 21 MB | x
2009 2.49b 17 MB | x
2009 2.50alpha 20 MB | x
2010 2.53beta 21 MB | x
2010 2.54beta 24 MB | x
2010 2.55beta 24 MB | x
2011 2.56abeta 23 MB | x
2010 2.56beta 23 MB | x
2011 2.57 25 MB | x
2011 2.58 27 MB | x
2011 2.59 30 MB | x
2011 2.60 34 MB | x
2011 2.61 41 MB | x
2012 2.62 40 MB | x
2012 2.63 40 MB | x
2012 2.64 45 MB | x
2012 2.65 53 MB | x
2013 2.66 55 MB | x
2013 2.67 65 MB | x
2013 2.68 64 MB | x
2013 2.69 67 MB | x
2014 2.70 67 MB | x
2014 2.71 81 MB | x
2014 2.72 83 MB | x
2015 2.73 86 MB | x
2015 2.74 88 MB | x
2015 2.75 90 MB | x
2015 2.76 92 MB | x
2016 2.77 108 MB | x
2016 2.78 116 MB | x
2017 2.79 121 MB | x
2019 2.80 117 MB | x