diff --git a/include/prototypes.h b/include/prototypes.h
index 5e193e66..254dc490 100644
--- a/include/prototypes.h
+++ b/include/prototypes.h
@@ -290,6 +290,7 @@ extern int blksize(int);
 extern time_t fdate(int);
 /* hap_fact.c */
 extern double hap_fact(struct natstr *, struct natstr *);
+extern double hap_req(struct natstr *np);
 /* hours.c */
 extern int is_wday_allowed(int, char *);
 extern int is_daytime_allowed(int, char *);
diff --git a/src/lib/commands/nati.c b/src/lib/commands/nati.c
index db8dacf0..6fdc412c 100644
--- a/src/lib/commands/nati.c
+++ b/src/lib/commands/nati.c
@@ -47,7 +47,7 @@ nati(void)
 {
     struct natstr *natp;
     struct sctstr sect;
-    float hap;
+    double hap;
     int mil;
     int civ;
     int cnum;
@@ -122,11 +122,9 @@ nati(void)
 
     pr("Max safe population for civs/uws: %d/%d\n", safepop, uwpop);
 
-    hap = ((natp->nat_level[NAT_TLEV] - 40) / 40.0 +
-	   natp->nat_level[NAT_ELEV] / 3.0);
-
+    hap = hap_req(natp);
     if (hap > 0.0)
-	pr("Happiness needed is %f\n", hap);
+	pr("Happiness needed is %.2f\n", hap);
     else
 	pr("No happiness needed\n");
 
diff --git a/src/lib/common/hap_fact.c b/src/lib/common/hap_fact.c
index 94efa32e..112f168b 100644
--- a/src/lib/common/hap_fact.c
+++ b/src/lib/common/hap_fact.c
@@ -62,3 +62,11 @@ hap_fact(struct natstr *tnat, struct natstr *vnat)
 	hap_fact = 0.8;
     return hap_fact;
 }
+
+/* Return happiness required to keep NP's citizens happy.  */
+double
+hap_req(struct natstr *np)
+{
+    return (np->nat_level[NAT_TLEV] - 40.0) / 40.0
+	+ np->nat_level[NAT_ELEV] / 3.0;
+}
diff --git a/src/lib/update/populace.c b/src/lib/update/populace.c
index eadb81bf..2bb5349a 100644
--- a/src/lib/update/populace.c
+++ b/src/lib/update/populace.c
@@ -49,10 +49,7 @@
 void
 populace(struct natstr *np, struct sctstr *sp, int etu)
 {
-    float hap;
-    float tech;
-    float edu;
-    float pct;
+    double hap, pct;
     int n;
     int civ = sp->sct_item[I_CIVIL];
     int mil = sp->sct_item[I_MILIT];
@@ -74,11 +71,9 @@ populace(struct natstr *np, struct sctstr *sp, int etu)
     }
 
     hap = np->nat_level[NAT_HLEV];
-    edu = np->nat_level[NAT_ELEV];
-    tech = np->nat_level[NAT_TLEV];
-    pct = (double)((tech - 40) / 40.0 + edu / 3.0);
+    pct = hap_req(np);
     if (sp->sct_own == sp->sct_oldown && hap < pct &&
-	chance(((double)pct - (double)hap) / (double)5.0)) {
+	chance((pct - hap) / 5.0)) {
 	/*
 	 * zap the loyalty of unhappy civilians.
 	 * there is a 20% chance per hap point below the