Predict birthday month from your NRIC

HTML

<h2>
Comparing methods to predict birthday month based on Singapore NRIC's numeric 6 digits.
</h2>
<br/>
<label>NRIC 7 digits (eg. S<b>???????</b>L)</label>
<br/>
<input type="text" maxlength="7" name="nric" id="nricfield"></input>
<button id="submitbtn">
Calculate Results
</button>
<hr/>
<div id="results">


<h3>Results:</h3>

<p>Which method is better? Not too sure..all these are speculation-based...</p>

<p>
1. someone's method:<br/> By 3rd and 4th digit?:<br/>
<a href="https://mathtuition88.com/2014/12/25/guess-birthday-month-based-on-first-4-nric-digits">https://mathtuition88.com/2014/12/25/guess-birthday-month-based-on-first-4-nric-digits</a><br/>
<input type="text" id="method1" readonly="readonly"></input>
</p>

<p>
2. My method:<br/> By average monthly births per year?: <br/>
<a href="http://www.singstat.gov.sg/statistics/visualising-data/charts/number-of-births-and-deaths">http://www.singstat.gov.sg/statistics/visualising-data/charts/number-of-births-and-deaths</a><br/>
<input type="text" id="method2" readonly="readonly"></input>
</p>

</div>

CSS

#results {
  padding:4px;
  background-color:#dddddd;
}

JavaScript

var SG_STATS = {
  "1960": {
    "births": 61775,
    "deaths": 10210
  },
  "1961": {
    "births": 59930,
    "deaths": 10027
  },
  "1962": {
    "births": 58977,
    "deaths": 10178
  },
  "1963": {
    "births": 59530,
    "deaths": 10138
  },
  "1964": {
    "births": 58217,
    "deaths": 10434
  },
  "1965": {
    "births": 55725,
    "deaths": 10263
  },
  "1966": {
    "births": 54680,
    "deaths": 10444
  },
  "1967": {
    "births": 50560,
    "deaths": 10523
  },
  "1968": {
    "births": 47241,
    "deaths": 10982
  },
  "1969": {
    "births": 44562,
    "deaths": 10224
  },
  "1970": {
    "births": 45934,
    "deaths": 10717
  },
  "1971": {
    "births": 47088,
    "deaths": 11329
  },
  "1972": {
    "births": 49678,
    "deaths": 11522
  },
  "1973": {
    "births": 48269,
    "deaths": 11920
  },
  "1974": {
    "births": 43268,
    "deaths": 11674
  },
  "1975": {
    "births": 39948,
    "deaths": 11447
  },
  "1976": {
    "births": 42783,
    "deaths": 11648
  },
  "1977": {
    "births": 38364,
    "deaths": 11955
  },
  "1978": {
    "births": 39441,
    "deaths": 12065
  },
  "1979": {
    "births": 40779,
    "deaths": 12468
  },
  "1980": {
    "births": 41217,
    "deaths": 12505
  },
  "1981": {
    "births": 42250,
    "deaths": 12863
  },
  "1982": {
    "births": 42654,
    "deaths": 12896
  },
  "1983": {
    "births": 40585,
    "deaths": 13321
  },
  "1984": {
    "births": 41556,
    "deaths": 13162
  },
  "1985": {
    "births": 42484,
    "deaths": 13348
  },
  "1986": {
    "births": 38379,
    "deaths": 12821
  },
  "1987": {
    "births": 43616,
    "deaths": 13173
  },
  "1988": {
    "births": 52957,
    "deaths": 13690
  },
  "1989": {
    "births": 47669,
    "deaths": 14069
  },
  "1990": {
    "births": 51142,
    "deaths": 13891
  },
  "1991": {
    "births": 49114,
    "deaths": 13876
  },
  "1992": {
    "births": 49402,
    "deaths": 14337
  },
  "1993": {
    "births": 50225,
    "deaths": 14461
  },
 ...