* Age group: Are we talking about 18-22 year olds, or all ages? The percentage of the population attending university in a given age range will vary.
* Type of institution: Does "college" include universities, vocational schools, or other post-secondary institutions? Italy has a diverse range of higher education options.
* Definition of "go to college": Does it mean enrolled at any point, currently enrolled, or graduated?
To get an accurate number, you'd need to specify these criteria and consult Italian government statistics on higher education enrollment and graduation rates. Organizations like ISTAT (Istituto Nazionale di Statistica) would be a good source for this data. You'd likely find the data presented as percentages of the relevant age cohort, rather than a raw number.