Lock them up. Throw away the key. If only it were that simple — and cheap.

Washington taxpayers spent nearly $345 million last year to operate the state’s prisons.

That’s about $95 per day for each inmate, the state Department of Corrections calcul

ates. That’s a bit more than Oregon spends and close to double what it costs in Idaho. But if you think prison is pricey here because inmates can ha

ve flat-screen televisions in their cells or attend yoga classes, guess again.

“The costs for TVs, yoga, family programs and most other forms of recreation are not paid for with taxpayer dollars,” corrections spokesman Chad Lewis said. “Virtually all of that is paid for out of the Offender Betterment Fund, which is money collected from offenders and their families. The biggest revenue source for the fund is collect phone calls.”Data show the prison system’s biggest area of expense — 75 percent — is compensation paid to workers. Indeed, nearly half of the spending is for salaries and benefits to corrections officers who do the dangerous work of keeping inmates under lock and key. Add to that the cost of people and supplies needed for humane confinement, including health care. On average, the state spends $18 a day per inmate on health and psychological treatment. That’s roughly a fifth of prison costs.

Costs vary from prison to prison and are influenced by a number of factors, including the level of security and the inmate population. Monroe, for example, has higher health care costs than average because some of the state’s most ill offenders are there so they can be near hospitals, Lewis said. Monroe also is home to the Special Offender’s Center, where mentally ill inmates are housed.

Here are some other numbers the corrections department supplied in response to a public records request:

•$159 million — Salaries and benefits for corrections officers.

•$62 million — Salaries and benefits for noncustodial prison staff.

•$46.5 million — Spending on goods and services at prisons.

•$38 million — Salaries and benefits for prison health care staff.

•$65.3 million — Total spent on health care.

Average daily cost per inmate in Washington’s major prisons

Institution Prison costs Health costs Average population Average daily cost Statewide $76.85 $17.99 14,950 $94.84 Monroe Correctional Complex $88.86 $28.20 2,514 $117.06 Washington State Penitentiary $98.74 $18.93 2,301 $117.67 Washington Corrections Center for Women $87.71 $33.10 873 $120.81 Clallam Bay Corrections Center $90.73 $8.99 895 $99.72 Stafford Creek Corrections Center $53.64 $15.49 1,955 $69.13 Airway Heights Corrections Center $56.92 $15.66 2,171 $72.58 Washington Corrections Center $72.57 $15.66 1,652 $88.23