Does "that" here refer to "the use of mental health services"?

Context:

BACKGROUND
Increasing mental health treatment of young people and broadening conceptualizations of psychopathology have triggered concerns about a disproportionate increase in the treatment of youths with low levels of mental health impairment.
METHODS
We analyzed the 1996–1998, 2003–2005, and 2010–2012 Medical Expenditure Panel Surveys, which were nationally representative surveys of U.S. households, for trends in outpatient use of mental health services by persons 6 to 17 years of age; 53,622 persons were included in the analysis. Mental health impairment was measured with the use of the Columbia Impairment Scale (range, 0 to 52, with higher scores indicating more severe impairment); we classified youths with scores of 16 or higher as having more severe impairment and those with scores of less than 16 as having less severe impairment.
RESULTS
The percentage of youths receiving any outpatient mental health service increased from 9.2% in 1996–1998 to 13.3% in 2010–2012 (odds ratio, 1.52; 95% confidence interval, 1.35 to 1.72). The proportionate increase in the use of mental health services among youths with more severe impairment (from 26.2% to 43.9%) was larger than that among youths with less severe or no impairment (from 6.7% to 9.6%). However, the absolute increase in annual service use was larger among youths with less severe or no impairment (from 2.74 million to 4.19 million) than among those with more severe impairment (from 1.56 million to 2.28 million). Significant overall increases occurred in the use of psychotherapy (from 4.2% to 6.0%) and psychotropic medications (from 5.5% to 8.9%), including stimulants and related medications (from 4.0% to 6.6%), antidepressants (from 1.5% to 2.6%), and antipsychotic drugs (from 0.2% to 1.2%).