"One out of every 20 kids has at least experimented with hard drugs such as cocaine [note that they admit this drug is not soft!] or xtc."
One out of twenty is 5%. Compare that with our government's numbers. According to SAMHSA's survey results for 2004 21.2% of all kids twelve to seventeen to 17 in this country had tried an illicit drug other than marijuana. That's five out of twenty compared to Holland's one out of twenty.
See Table 1.68B (Illicit Drug Use Other Than Marijuana)
http://oas.samhsa.gov/NSDUH/2k4nsduh/2k4tabs/Sect1peTabs68to72.pdf