Burglaries dropped 7.3 percent last year while motor vehicle thefts rose 11.4 percent, according to a government survey of victims that indicated the total number of crimes was virtually unchanged from 1988.

The National Crime Survey released last week by the Justice Department estimated that the number of personal crimes of violence and theft against Americans dropped 1.4 percent last year while household crimes including burglary and motor vehicle thefts increased 1.9 percent from 1988.The rates of all types of crime covered by the survey, except motor vehicle thefts, were lower in 1989 than in 1973, when the first survey was completed, the Justice Department said.

The rate of personal crimes was 20.9 percent below the 1973 level while household crimes were down 22 percent from 17 years ago.

Motor vehicle thefts were up 0.5 percent from 1973, a difference the survey found was statistically insignificant.

The estimated rate of violent crimes last year is 10.6 percent below the survey's figures for 1973.

The estimates, based on interviews with 97,000 Americans age 12 and older, contrast sharply with the picture of crime trends painted in the FBI's latest compilation of state and local police figures.

The FBI's Uniform Crime Index found that violent crime soared 10 percent during the first half of 1990, with murders increasing 20 percent in the nation's largest cities.

The FBI figures, released Oct. 19, are based on crimes reported to authorities while the National Crime Survey includes crimes that victims said they did not report to police.

The 8 percent increase in murders in the FBI's crime index results from the "internecine war that occurs in the drug trade, there is a lot of that," said criminologist Marvin Wolfgang.