Mean standard deviation scores for singleton births in the Townsend quartiles
| Year | Lower quartile | Mid-lower quartile | Mid-upper quartile | Upper quartile | All |
|---|---|---|---|---|---|
| 1990 | 0.18 | 0.16 | 0.02 | −0.03 | 0.08 |
| 1991 | 0.18 | 0.17 | 0.09 | −0.02 | 0.11 |
| 1992 | 0.18 | 0.13 | 0.17 | 0.07 | 0.14 |
| 1993 | 0.22 | 0.12 | 0.08 | −0.09 | 0.08 |
| 1994 | 0.25 | 0.19 | 0.11 | 0.00 | 0.13 |
| 1995 | 0.23 | 0.16 | 0.11 | −0.04 | 0.11 |
| 1996 | 0.23 | 0.12 | 0.04 | −0.02 | 0.09 |
| 1997 | 0.12 | 0.13 | 0.06 | −0.12 | 0.04 |
| 1998 | 0.19 | 0.10 | 0.08 | −0.09 | 0.06 |
| 1999 | 0.24 | 0.15 | 0.13 | −0.01 | 0.12 |
| 2000 | 0.29 | 0.20 | 0.24 | 0.07 | 0.19 |
| 2001 | 0.26 | 0.18 | 0.21 | 0.07 | 0.17 |