HAWKINS COUNTY, Tenn. -

A violent sex offender in Hawkins County is under arrest for failing to report his status. Billy Wayne Spears was convicted of the rape of a child in September of 1994.

He was classified as a violent sex offender and was required by the Tennessee Sex Offender Act to report his whereabouts quarterly. Spear hadn't done so since May 2013.

While checking these facts, we found more about the number of sex offenders registered in the state -- and the number may be shocking.

According to the website parentsformeganslaw.org and the Crime Victims Center, there were 19,562 registered sex offenders in Tennessee as of June 2013; that puts the state tenth overall in the United States..

In 2005, Tennessee had way fewer registered sex offenders, around 7,500. Back then, the Volunteer State ranked 22nd.

So why the jump? We dug deeper and found out the sex offender registry law in Tennessee got tougher. According to the TBI, the registry started in 1995. By 2004, the Tennessee Sexual Offender Act went into effect. In 2005 the number registered was 7,873.

We spoke with TBI spokesperson Josh Devine, who told us that by 2007 all eligible offenders in the state, including those on judicial diversion, were required to register. The number then spiked to more than 9,300.

In 2010, sex trafficking became a registerable offense.

In 2011, all sex offenders in jail were required to register -- that accounts for the 4,000-person jump that year.

The following year, promoting prostitution was added to the list of registerable offenses.

So how did Spears fall through the cracks and have his status remain unreported for more than a year? We'll continue to dig to find out those answers. We'll report on that when we learn more.

Visit parentsformeganslaw.org for the full list.