Domestic violence just “something that happens”?

A Northern Ireland crime survey for the Northern Ireland Office for 2003/2004 has found that 11% of men and 19% of women surveyed have been victims of domestic violence.
Incredibly, the number of those who considered it “wrong but not a crime” increased from 29% in 2001 to 35% in 2003/2004 while those who consider it just “something that happens” dropped from 27% to 16%.Overall, only 39% of respondents felt the worst incident of violence they suffered was a crime, up 2% on 2001, while 55% of victims did not consider their worst incident to constitute a criminal offence.

The report says this emphasises a widely held view in Northern Ireland that domestic violence per se is not a criminal offence.

65% of those victims who considered the abuse a crime failed to report the incident to the police while 92% of those victims who didn’t failed to do so.

Other findings:
15% of Protestants and 17% of Catholics experienced abuse.
Belfast has the highest rate with 21%
One third of female victims suffered violence while pregnant while over half say the violence started when they were pregnant.
67% suffered injuries in their worst incident.
80% of the worst incidents were not reported to the police.

Why do so many victims of domestic abuse not consider the violence perpetrated against them a criminal offence?