For privacy turn off your cell as you enter Nevada

Pew Research produced this interesting graphic.It shows the number of authorized wiretaps broken down by state. There doesn't seem to be any red state, blue state dichotomy nor is any one region of the country most apt to be bugged. The top 4 states account for about half of the wiretaps and contain about a quarter of the country's population. What is up with Nevada? Pew cannot discern any reason and Nevada law enforcement would not reply but most were issued in Clark County, which contains Las Vegas.