function gray_on(id) {
 document.getElementById(id).style.backgroundColor = "#f0f0f0";
 return true;
}

function gray_off(id) {
 document.getElementById(id).style.backgroundColor = "transparent";
 return true;
}

function toggle_content(id) {
 document.getElementById(id).className = document.getElementById(id).className == "style1bo"   ? "style1bc"   : "style1bo";

 for(year=1994;year<=2027;year+=1) {
   if ( document.getElementById(id+year) ) {
      document.getElementById(id+year).style.display    = document.getElementById(id+year).style.display    == "inline"   ? "none"   : "inline";
      document.getElementById(id+year).style.visibility = document.getElementById(id+year).style.visibility == "visible"  ? "hidden" : "visible";
   }
   if ( document.getElementById(id+year+'s') ) {
      document.getElementById(id+year+'s').style.display    = document.getElementById(id+year+'s').style.display    == "inline"   ? "none"   : "inline";
      document.getElementById(id+year+'s').style.visibility = document.getElementById(id+year+'s').style.visibility == "visible"  ? "hidden" : "visible";
   }
 } 
 if ( document.getElementById(id+'blank') ) {
    document.getElementById(id+'blank').style.display    = document.getElementById(id+'blank').style.display    == "inline"   ? "none"   : "inline";
    document.getElementById(id+'blank').style.visibility = document.getElementById(id+'blank').style.visibility == "visible"  ? "hidden" : "visible";
 }
 return true;
}