The information is intended to provide an indication of population immunity, based on antibody testing results in antenatal serum specimens received during the designated year.
| Year | Age group (years) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| <20 | 20-24 | 25-29 | 30-34 | >34 | ||||||
| No. tested |
% | No. tested |
% | No. tested |
% | No. tested |
% | No. tested |
% | |
| 2001 | 749 | 96.5 | 4001 | 91.1 | 9042 | 91.6 | 7582 | 92.1 | 4332 | 89.9 |
| 2002 | 551 | 95.5 | 3338 | 90.4 | 9979 | 91.6 | 7036 | 92.1 | 3799 | 91.8 |
| 2003 | 427 | 95.3 | 2215 | 92.0 | 5483 | 91.4 | 4991 | 91.3 | 2674 | 90.3 |
| 2004 | 625 | 94.6 | 3918 | 91.8 | 8925 | 91.3 | 9061 | 90.7 | 4462 | 90.3 |
| 2005 | 594 | 92.8 | 4043 | 90.7 | 8087 | 89.8 | 9441 | 91.1 | 4925 | 89.5 |
| 2006 | 660 | 91.5 | 3800 | 90.3 | 8143 | 90.4 | 10036 | 91.2 | 5292 | 89.1 |
| 2007 | 616 | 91.5 | 3453 | 90.9 | 8185 | 92.4 | 11065 | 92.4 | 6128 | 89.7 |
| 2008 | 602 | 89.0 | 3419 | 92.5 | 8527 | 92.5 | 11096 | 91.8 | 6365 | 89.8 |
| 2009 | 509 | 95.7 | 3346 | 90.1 | 8339 | 91.7 | 10929 | 91.8 | 6672 | 89.3 |
| 2010 | 538 | 84.8 | 3406 | 90.3 | 8800 | 92 | 11025 | 92.5 | 7187 | 90 |
| 2011 | 447 | 89.4 | 2898 | 90.9 | 9010 | 93.6 | 12273 | 94 | 7552 | 91.7 |
| 2012 | 510 | 85.3 | 2653 | 91.2 | 8640 | 93.9 | 13340 | 94.8 | 8113 | 91.5 |
| 2013 | 480 | 82.3 | 2363 | 89.3 | 7960 | 94.8 | 13106 | 95.9 | 7776 | 93 |
| 2014 | 410 | 85.3 | 2408 | 87.5 | 8387 | 94 | 14235 | 95.5 | 8408 | 92.3 |
| 2015 | 426 | 85.7 | 2385 | 87.9 | 8246 | 93.6 | 13860 | 96.1 | 8472 | 94.3 |
| 2016 | 368 | 87.8 | 2251 | 85.3 | 8034 | 92.9 | 13756 | 95.9 | 8499 | 94.8 |
| 2017 | 311 | 87.1 | 2021 | 82.6 | 7009 | 90.5 | 12195 | 95.8 | 8267 | 94.8 |
| 2018 | 260 | 85.8 | 1822 | 82.1 | 6771 | 88.2 | 12326 | 95.7 | 8620 | 95.2 |
| 2019 | 218 | 88.1 | 1588 | 83.6 | 6303 | 87.8 | 12077 | 95.1 | 8400 | 95.1 |
| 2020 | 177 | 95.5 | 1105 | 90.2 | 4576 | 92.6 | 9708 | 95.9 | 6766 | 95.1 |
| 2021 | 133 | 96.2 | 903 | 91 | 4254 | 91.5 | 9243 | 95.5 | 6797 | 95.8 |
| 2022 | 113 | 96.5 | 712 | 91.4 | 3582 | 90.8 | 8140 | 95 | 6055 | 95.4 |
| 2023 | 81 | 90.1 | 711 | 91.3 | 3644 | 89.7 | 8703 | 92.5 | 6618 | 94.7 |
| 2024 | 92 | 92.4 | 649 | 91.4 | 3354 | 87.5 | 8221 | 91.1 | 6717 | 94.0 |