Allow no colnames with PDF output when booktabs enabled
diff --git a/R/group_rows.R b/R/group_rows.R
index 85962cf..d3871f7 100644
--- a/R/group_rows.R
+++ b/R/group_rows.R
@@ -162,8 +162,12 @@
   }
   if (italic) group_label <- paste0("\\\\textit{", group_label, "}")
   # Add group label
-  rowtext <- table_info$contents[start_row + 1]
   if (table_info$booktabs) {
+    if (is.null(table_info$colnames)) {
+      rowtext <- table_info$contents[start_row]
+    } else {
+      rowtext <- table_info$contents[start_row + 1]
+    }
     pre_rowtext <- paste0(
       "\\\\addlinespace[", gap_space, "]\n",
       ifelse(hline_before,"\\\\hline\n", ""),
@@ -174,6 +178,7 @@
       "}\\\\\\\\\n", ifelse(hline_after, "\\\\hline\n", '')
     )
   } else {
+    rowtext <- table_info$contents[start_row + 1]
     rowtext <- paste0("\\\\hline\n", rowtext)
     pre_rowtext <- paste0(
       "\\\\hline\n\\\\multicolumn{", table_info$ncol, "}{", latex_align,"}{",